Welcome acwild! Always room for another Browncoat.
FYI, that Jayne pistol isn't the "actual pistol Adam Baldwin (Jayne Cobb) used in the series". That's birdie's replica, he's a member here (that particular piece is not
too terribly screen-accurate. BUT I suspect he has a newer one that is spot on).
Not sure of the lineage of the Callahan photo.
And the Mal pistol in the photo is also not the screen-used piece. That one is the 'Model 47' (IIRC), & it was made by an RPF member also (I believe one WAS gifted to Nathan Fillion, but it was many years after the series ended).
You can find quite a few photos of the actual screen-used weapons over at
The Firefly Archive, if you're interested.