Curtis
I know all orginal 29,s have a 0 on the left side of the grip frame.

I dont know about 22,s
the only ones that I have researched are the ones that share common frames. N frames
this also works for fixed sight guns
44 specials that were were reworked from Heavy duties or were build as 38 and converted to 44,s
Not many people know about this until now
you learn by making mistakes buying guns
that have been put together.

my guess on this gun on this thread is it has been put together because the stamping does not look right. it could be factory converted which means it will not letter.
jim