How do you mean, the difference and so many part numbers?
Just had a quick poke at the parts catalogue and I only get two numbers
VIN number JA032849 (1992) = part number FRC8005
VIN number JA032850 onwards = part number FTC3188
Not sure of the difference - could either be when they changed over to 24 splines from 10 or maybe when ABS came in (I think the stubs are the same whether you have ABS or not tho)
I bought a rear one for my 300 (3188) December 02 which was about 40quid I think. Thing wasn't finished properly tho so I ended up re-using the existing one after playing with the angle grinder on the old bearing welded to it!