Nope. Magnum stamped frames only go to 340000.
All 6-1/2" Single-Sixes with fixed sights after 400000 are going to be convertibles (no mag only guns known to letter, though never say never)
There are only 13 Sigle-Sixes known to be shipped as RSSMW that aren't Magnum marked in the 340000 to 400000 range.
Ruger's website is incorrect for listing Magnum only Single-Sixes beyond serial number 400000 as production pretty much stopped in 1964.
Chet15
Chet you state in the RENE that the Magnum stamped frames go to 340086.
But in the Dates of Manufacture you list
1962...........331116 to 344019
and 349909 to 3511441
1963..........351442 to 380391
1964...........380392 to 394740
So was production stopped in 1962 or 1964 for Mag marked guns????? Just curious.
I have S/N 339948 with Eagle on the barrel which could be 52 from the the end of production.. A pretty scarce one which is one of 700.