“S” marked MKI/II/III

[t.hinckley]

Why is one roll marking upside down?

It's called an "OOPS".

[rpm enterprises]

The up-side down rollmarks belong on the other side of the receiver. Who is to say but could have been done as a joke or maybe that employee had a hang over. I've never witnessed how that process is actually done at the factory. Just another variation collectors like.

[chet15]

Why is one roll marking upside down?

The receiver was jigged into the rollmarking machine on the opposite side of what was supposed to be. Probably talking to somebody and lost his train of thought.
Chet15

[Rickkling]

RPM, (sorry, I don’t know your name)
Mine is a RST-4
11-22615