I think the 'S&W' on the bbl and the Logo on the LH sideplate have been added.
The bbl marking when looked at very closely looks like an acid etch with hand engraving clean up.
The letters don't match in height especially the 'S's. The vertical bars of many of the letters are less than vertical. The tips or ends of the elements of letters very often have a spear point shape. Sure sign of a v-point chisel being used to cut/recut the letter portion and done carelessly if trying to mimic a roll-die.
The Logo looks like maybe a stamp and some hand engraving involved.
If you look closely again, the process of placing the Logo on the sideplate took a couple trys.
There are the faint partial stamp marks of the circular outline of the logo in the 2oclock position
Plus a little of the bars of the 'E' in the word Trade at about 1oclock just above the word TRADE.
Way outside of that there is another divot of a sort. That my have been left over from the orig mfg's logo, though just a guess on that. There has been a lot of filing and metal removal in that area through.
On the inside of the grip strap frame on the RH side,,a factory work mark of 1 45 (?)
Is it a for real mark, a purposely done fake mark, or maybe something done by the orig mfg if othr than S&W.
The ser# looks like a Spanish revolver # to me.
No caliber marking
The grip pin placement has been noted.
Just some stuff I see.