suzuki gt brake master cylinders

[dollydog]

is there, anywhere, a list which explains the numbers stamped on the underneath of the front master cylinders? only asking because the half dozen or so spares i've got all seem to have different numbers on them, and i'd like to know what they were off originally. they are all gt suzuki fronts. many thanks if you can help
cheers, dd.
p.s. a couple of different ones i have say O A 1 and O K 3 on them. these are the numbers i need to work out please.

[Hush]

The only stamp i am aware of is the "D" which indicates the master cylinder is designed for double front disc activating as in the later model GT550 and GT750.

[daxman]

Can't help I'm afraid - MY 250 is wearing a GS500 m/c. Seems to work ok and has the added bonus of a sloping reservoir to compensate for the 'Ace bars'..

Cheers

J