The chassis plate on BMW is located on the left-hand door sill and shows the name of the company who built the shell, i.e. who installed the roll-cage. Though the 1980s and early 1990s construction of most shells was contracted out to German company Matter.
For the E36 3-series built during the early 90s, chassis numbers were in the format E36/XXX NNN YY

E36	Model designation
XXX	Vehicle specification CL2 FIA Class II A Group A N Group N 1 Early BTCC 2-litre class coupe
NNN	Sequential number. The number is specific to the E36 model rather than to the year of manufacture, so the sequence just continued from one year to the next. The number wa initially 3 digits in length with leading zeros, changing to 4 digits in length in late 1993. The first car built to 1993 spec was 048. 0084 was the first 1994 spec car, built in Sept 1993. It's believed there were a total of either 128 or 129 cars built, which includes all specifications. BMW's own records are a little vague on the exact number.
YY	Year of manufacture

From 1995, production of the shells moved in-house to BMW Motorsport. For these later cars, chassis numbers were in the format E36 XXX YY/NNN

E36	Model designation
XXX	STC - FIA SuperTouring
YY	Year of manufacture
NNN	Sequential number. The number is specific to the year of manufacture, restarting at 001 each year. There are a number of cars which have a single character suffix after the number. For example, 95/032E was an endurance spec built for the Nürburgring 24hrs; confusingly there is also a 95/032. There is also 96/047C, which is the new number given to 96/003 following extensive repair, or possibly haven't been re-shelled.