First thing to do, is to get the VIN off of the steering head, and then go to RealOEM.com and put the last 7 characters of the VIN into the search box. That will tell you the month and year the frame was manufactured. On the engine case , on the left side at the front, there should be a machined area, and it has a serial number, and it usually is the same as the frame number. But after 25 years and who knows how many owners, it's impossible to know for sure what's been done to the bike, as to whether the bike came out of the factory that way, or has had the engine changed. If you really wanted to do some research, you can call the BMW customer service number, and see what, if any information they may have on the bike.
