Bill & Group,
Per SIG 5-1, August 1944, the Sig Stk Nr's for the three mounts are:
FT-301-A 2Z6721-301A
FT-302-A 2Z6721-302A
FT-335-A 2Z6721-335A
These would be in SIG 5 Subclass 2Z Part II. I only have 1947 and 1955,
both of which skip over these numbers. So they went away prior to 1947.
73
Robert Downs
<[email protected]>
Houston