My 1950 Auster has quite a few parts stamped 1949. And each part has its own stamp and manufacturing date so Morgan, being of the same era and ilk, is likely to follow the same procedure. Just a guess.

1968 4/4 1600
1950 Auster J5B
Kitfox S5 Outback
Jodel D9
1988 Peugeot 205 GTI 1.9