gearbox years by serial numbers

[incisor]

can you roughly tell the year of a pre suffix series gearbox by it's serial number?

[B.S.F.]

A Series 1 box you can. I'm afraid I'm not taking much interest in later stuff. .W.

[Dgd69]

Think on early series 2 the gearbox year is the fourth number like the engine number eg 1519xxxxx is a 59 then with 2a /3 used suffix letter I think