Nickel S&W 39-2 stamped with H and T on frame?

[Draw4u]

I recently bought a nickel 39-2 made in 1981. I took it all apart last night to see condition and noticed a capital H on part of the frame and a capital T. Both of these are stamped on the bottom, near the magazine well. Any idea what these mean? I also looked at my other 39-2's (blued) and one of them is stamped with a Q and the other is stamped with a B.

 

[lhump1961]

I have 4 39-2's...2 blue and 2 nickel. Only the nickel have marks as you've indicated and I'm sure they don't mean anything outside of the factory. Maybe someone else knows more.

 

[Draw4u]

I contacted S&W and they said these are a fitters stamp that was put on the firearm during inspection.