There are a few of the different models here:
My understanding is that the basic turbo has been the same from the start, with the exception of the special edition ones, and the offshoot ones. Selle Italias have a date code dial on the bottom with the month and year.
I¹m pretty sure the turbo came first, then the world champion version, afte r some sort of win, has gold nose plate and single gold rear plate, plus I think this is when they started adding stripes to the packaging rather than the two tone versions. Then the Hinault model, the supperleggra, the pro team, forced, bio, turbo-matic, SL/SLG (more padding), L/Lady, Super and o n and on (not necessarily in that order). Not to mention a bunch of limited edition ones with embroidered patterns and such.
Check this auction for an example of the date code:
I sorta¹ have an obsession with these, (if it¹s not already obvious).
San Francisco, CA