Hi there folks,
I've recently been researching quite a bit about part numbers (or more precisely: 'Design IDs' as TLG calls them) but kinda ran into some odd ends. This is up to a point, where I had hoped someone who has been longer up into the online community and early LUGs (or however else you got that knowledge :D) could shed a little light on this.
Before I start up with the main problem, here is what I've been able to find out thus far:
Prior to '96 part numbers used to be 4 digits each, starting with the slightly strange choice of 3001 (2x4 brick) as the presumed starting point (though I have a few theories about that number choice, placeholders etc.).
While I don't know when this system was actually introduced, it seems awkward that it holds up pretty well with the actual release history of the elements even for VERY old parts. 'Mini Fireman Helmet' for example has number 3834, which in itself lies in a whole cluster of part IDs belonging to the initial Minifigure Town release in 1978. The 'Mini Cap' (Old Policeman's/Conductor's Hat) on the other hand has a number of 3624, which totally fits this, as it was released quite a few years before the first minifig, as part of the mid 70's 'proto-figs'.
The system from numbers 39XX forward remains pretty constant in that scheme, with 2 jumps occuring.
In around 1987 (compare some Futuron/Blacktron I Parts) the numbers suddenly changed down from 4XXX format (after 39XX (ca.1979), they had to advance a number) to 23XX-26XX. Sometime around that point, they also decided to put Technic parts in their own gap of numbers, that somehow collided with many 12V and 9V Train elements. The numbers are 27XX-29XX ending roughly around 1994/1995 (check '94 8880 Super Car for example, many exclusive pieces).
20XX-22XX has a few Duplo and Fabuland Parts in it, as well as a very huge bunch of gaps.
Since they were eventually running out of numbers again, they switched a second time around 1991. The parts from then on were identified by numbers 6XXX, with System (including Basic, Freestyle and even Belville) having numbers 60XX-62XX and Technic being in the 65XX range (again mixed up with Trains). There were also a couple of Duplo Toolo elements in the 62XX numbers as well (if Bricklink's entries are correct).
Perhaps in attempt to avoid further number jumps and similar stuff, they finally switched to a 5-digit system around 1995/96. This is kind of similar how they switched the color code system from 2-digit to 3-digit in 1997 and the set number system from 3- to 4- (1980) and finally to 5-digit in 2012. Curiously the new system started again with a 3 - '30000 - Bearing Element 2x2 w.d. Snap'. Kinda seeing a pattern here :)
So my guess for the start of the current numbering system would be one of the following years: 1955-58 (first modern bricks), 1986 (first jump), 1991 (second jump) or 1996 (change to 5 digits). Also note that part numbers didn't appear on actual bricks up until the early 1980s. I might also be totally wrong here , ugh...
What makes me wonder though (and here starts the real question) is that today there are no official indications whatsoever, that the number range below 2000 was ever used for parts.
Strangely though Bricklink, Peeron and LDraw know quite a few of those parts with less than 4 digits. I kind of guess the 3 mentioned databases have some common origin that might predate 2000 or something, I just don't know the exact history here (Lugnet and Brickshelf were also kind of a big thing back then I remember...).
We all know there are some parts, whose geometry doesn't allow for a design ID to be put on the actual part without compromising it's look or function, like many minifig tools. Whenever this was the case, fansites back in the day, when official TLG info was scarce, they numbered it simply with an 'x' followed by an individual number, like 'x70 Headgear Hat, Rag Wrap / Bandana'.
(well there are other types especially for electric type assemblies, where the number is a short term for the actual part, followed by some alphanumericals)
However, there are a few examples, where they have some numbers that they seem to claim or believe are official. Most of them from around the 1970s or from some sort of pre-assembled elements. One rather odd (though presumably well known example) is '983 Hand'. Problem is Customer Service and LDD (both official TLG sources) call this part '3820 Mini Hand', which fits way better to the other elements released around 1978 and the number pattern in general.
Most other standard minifig parts have the same phenomenon.
So anyone any idea how that came into being? An earlier numbering system predating ca. 1984? Numbers received from customer service or some insiders? Misinterpretation of mould position numbers?
Well, long text, hoping for comments and thanks for answers^^