T206 Cy Young Bare Hand Shows - Proof?

[REDSOX_1969_LIVERPOOL FC]

Hey guys -

I have a T206 Piedmont 150 Cy Young Bare Hand Shows that PSA graded a 1. It's a nice card that has seen better days, but it's definitely not a beater.

One aspect of the card that has always been interesting to me is the printer's registration mark on the lower right back side. It's in the same bluish colored ink as the rest of the Piedmont 150 back.

I've seen various examples of T206 "proofs" before (e.g., the Olbermann proofs), but in those examples I see registration marks on all 4 sides of the card, and I see the registration marks in the various different colors used in the lithographic process back in 1909-1911.

So what is this mark? If it were a registration mark for the printer to align the various layers of color on the card, where are the registration marks in different colors?

Anybody ever see this before, or have any insight?

[packs]

A proof would have to be an unfinished card. If it is a printers mark it's miscut. But it kind of looks like a pen mark to me.

[sb1]

It's a mark for cutting the sheets, often found on cards that are either oversize or miscut.

[Leon]

I don't think I have seen a mark like that before. I have seen lots of printers marks and like them.