A Question On The Back Of A SC 2506

i have a sc 2506 and the back has a red checkerboard like pattern on the back.
i soaked the stamp I water just to see if there would be a change.

is this just from the paper it was attached to?

thanks

dan

I would say definitely yes, it is from the paper the stamp was attached to. If you blow up the reverse image and look at it closely, it appears the area to the left of the solid line has the reference "Place Stamp Here" (or something similar).

As a matter of fact, I've seen direct mail reply envelopes come in my mail from The Salvation Army and some of them use their red shield logo as the basis for the security printing inside the envelope. The shape of the patterns on the reverse right side of the stamp you show suggests to me it may be miniature logos from that organization. (Just a guess.)