Security Bank Note Co. Proof, Can Someone Give Me Insight To This Piece?

Unsure what this item is categorized as, but hoping some of you can help to shed light.

Thank you in advance.

I don't have much sense of scale on the size of this piece, but the top picture looks much like the back of a bond coupon. Typically 30 or 40 of these were attached to a coupon bond, for semi-annual interest payments, but sometimes there was an odd number of coupons that didn't entirely fill a sheet. In some instances, the bank note company filled the "holes" with a generic design. Your piece may have been clipped from a sheet like that.

Yes, the scale appears to be similar.

Appreciate the info and the comparison.