maybe the amp is a PP with 2 6V6's and someone stuck a wrong tube from a radio in the other 6V6 socket..
however, if you find under the hood that all sockets are wired correctly, and that there is no PI, and the OR is an SE..... it might be original.
magnatoneamps.com is my website, and I made that chart. It's important to point out (and I should do so on that table) that it was not from an authoritative source that I compiled that data. It is based on observations of amps that I have found on auction sites and websites over several years. I listed those tube compliments but not at the exclusion of others.
They changed tube line-ups quite a bit in those days. you'll see elsewhere on the list tube line-ups changed for the same model number.
I'd do some close examination of your example, it might be the original line up. (1) going from PP to SE is no small task, it's easier to find an SE amp, or if replacing broken parts, its easier to find a PP OT, or another 6V6.
if the OT has a date code that's near the other date codes, and if all the solder joints and components look the same, or close to it., its probably original. and given that the modification would have probably had to have happened a long time ago, you gotta ask, 'who would go to all that trouble?'
Also, the -5 in M-195-5 means 5 tubes. (like -4 in M-194-4 and -3 in M-197-3...)