Nice find for sure!
That trigger guard can be restored and should be IMO.
357 prewar SAA's are not common.
A Colt letter is the only way to verify the original spec it left the factory just like S&W.
Maybe you have one already and the rest doesn't apply..
If the bbl is a pre-war from that late 30's/1940 era,,there was one of the 'broken die' characteristics that shows up in that serial number range of single line bbl address SAA's. (5 1/2 & 7 1/2")
The 'o' in Hartford on the roll die chipped and a small piece broke out leaving an incomplete circle for the 'o'.
If the bbl was a Post WW2 replacement (2nd Gen), that break would not be there.
Post war, many 1st gen SAA's were rebbl'd and cyl'd to 357.
The gun could have started life as a pre-war 38Colt Spcl.
The cyl being orig would then have been simply reamed for 357 like was done on the S&W 38-44HD's.
I think 1940 would have been too late for a plain 38Colt chambering. If not it would have been the chamber style with the shoulder,,
A replacement bbl in 357 marking, pre-war or post-war vintage could have been added at any time afterwards due to damage, want of a shorter/longer bbl, ect.
I'm not saying that the OP's gun is not a PW .357,,it's just that like a S&W, it takes a letter to confirm what it left the factory as.
..and SAA's are quite easy to switch caliber parts on.
If it was a 38 Colt Special from 1940,,that wouldn't be entirely bad either.
Only a small number of those were turned out and many went over to England in the request for small arms in the Battle of Britain.
A letter may list it in 38Special caliber as simply 38C,,,or 38Colt,,or 38 Colt Special.
Most in 38 Special were logged as the first 2 ,,(38C or 38Colt).
So when they tabulate the totals for '38 Colt Special', the number comes up very small. The actual count is likely greater when the others are figured in , but there's another one of those collectors arguments at can lead to headaches that I tend to stay away from.
Great case color on the SAA. The hammer looks like it has the polished sides and should have blued edges.
Just a great find,,congrats!.
Garage Sale,,,just lying among the baby items and Disneyland souvenir glass ware. Not in my world!