Franklin 1 Cent With Plate Block With Blank Plates Chr Engraver

Can anyone give me any information on the significance of the engravers initials on a 1c Franklin in a plate block with three blank stamps.

The entire test reads:

F.A.G. CHR

Thanks!

not without a photo. front and back. otherwise its a guessing game as to what you have.

Front attached. Can get a picture of the back when I get home. Thanks.

Initials can mean different things, but these are initials appear to be siderographers and plate finishers. They typically appear in the margin adjacent to a corner stamp much like a plate number. From John Meek's article "Initials of Siderographers and Plate Finishers" in the February 1969 US Specialist, pages 66-68, there is a FAG = Frank A. Green and a CHR = Charles H. Roll both listed as plate finishers.

Add: Here are two more stamps with initials:
DWMcC = Daniel W. McCallum, siderographer (note, in LL corer)

RJL = Robert J Little
WWM - Willaim W Malone, plate finishers (note, in LR corner)

Thank you!