They take your numbers so they can be sure they have the right parts for the car for the service. For the most part the main dealers parts section has gone down hill

I have a few makes who used to work for i.e Jag & Toyota, They were replaced with monkeys who could use a PC. They know nothing of the car or different versions so its very much a "computer said no* situation. It was with a view to keeping costs down.
So yes, it is completely normal in my own experience.
Lets look at it this way, what are there, 7 variants of coupe?
16v
16vt
20v
20v vis
20vt
20vt + 6 speed
20vt LE 6 speed
hell, there is even late 20vt's with a 6 speed
then there are the sub changes with in each model, early 20vt's have a different dash than the later 20vt's (that's the only obvious one that most people will know.
I suppose one could say there just not opening them self's up to a mistake