Many types/versions but main difference between most is the amps output, some have the 3 pin plus and later ones have the main power lead held on with an M6 nut, ie 10mm spanner size, theres also universal ones that will fit either car.
Ebay search A127 alternator, if yours has the plug buy the plug version and if yours has the nut version buy that.
My 1993 200tdi has the nut version, slightly earlier disco engine has the plug variety.
Doesnt matter what hand you buy as 5 minutes with a spanner will sort it.