REA lot 166 Red Hindu Mystery?

[ullmandds]

I was perusing my REA catalog while in the tub last night...and I noticed that the Walter Johnson w/Red Hindu back...has had a mark removed from the back...which is/was not noticeable on the web site but is pretty clear in the catalog.

I have owned three red hindu's in my day...2 of which had a 7-c marked on the back in what appears to be a wax pencil or crayon. I believe Jeff L has the Chase...which I sold a few years ago.

I purchased my 2 red hindu's in an auction in silver spring, MD in the early nineties...of which there was a 3rd...elberfield fielding.

I have never seen the same 7-c mark on any other t-cards...besides the 3 red hindu's at the auction in MD...and now the Johnson that just sold in REA. Does anyone have any insight what this 7-c may mean...or has anyone seen any other cards with this mark on the back?

Peter Ullman