That's the only Brill I have seen with a hammer protector for a double
action revolver. Turnerriver shows one above for a single action. I have
a reproduction by Doc Barranti, shown above, for a double action. I wish
there was a way to date that holster. I have studied a lot trying to find
out who first put a hammer protector on a holster. So far my money is
on Wally Wolfram in the 1940s.
The Father, August Brill, started Brill in 1912. He did a lot of floral carving,
but don't think he put the Brill name on the front. The famous Butch
Cassidy holster has the name on the back for example.
The Son, Arnold aka "Arno" did put the name on the front, but
it seem that most of his were basket weave.
I suppose either one of them could have made your holster.
You have an interesting specimen there.

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In Omnia Paratus