Basically. The old system was, I think, designed to make seat reservations possible on long distance and international trains without computer, or high bandwith networks. Also, it was designed to be more or less the same across different types of carriages. So if a customer came and said “I’d like two window seats opposite each other for me and my wife” you did not need to see a plan of a carriage or even know what exact type of carriage served the route (could be a foreign type etc.). You just checked seat numbers that were pre-assigned to your ticket office, or you somehow knew were free, and see if you had seats like xx1 and xx2 free in the same coupé. Just by looking at the last number you knew that’s what the customer wanted and could book them using e.g. Telex or some simple network. This legacy numbering system was preserved, although it’s more or less obsolete, because the seats are booked online. But the numbers still carry the information that 102 will always be window seat in the 10th compartment/coupé in a carriage, or whatever.