“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.