A727 TorqueFlite Transmission ID

Hey Transmission Gurus,

I need a little help identifying a 727 TorqueFlite Transmission. I think the number stamped into the rail just above the pan on the driver’s side is,
“PK40 9538 5884 8211”. The “P” could be a “B” and the 11th digit could be a "6” instead of an 8.

I found this document on the Web,
http://www.mymopar.com/downloads/transguide.pdf
But I can't seem to correlate any of the numbers above as they're all seven digit numbers. I found a couple other numbers cast into my bell housing that may help with ID. They are "3748102-7" and "4028101".

This transmission was backing up a 360 LA and came out of a 1975 Dodge Sportsman Motorhome. I assume this was the original transmission as it seemed to be unmolested.

Can anyone tell me what I have? Any known problems (other than linkage mods) using this in my A-body?

Thanks,