Jon, I've certainly never seen another like this one. I have seen one of the engraving patterns before. It is the one with 'rolling rabbit' and it was on a Browning product of some sort and there has been speculation that the hunter in the engraving is meant to portray John M. Browning himself.
Someone has suggested that FN outsourced all it's engraving until sometime in the 1920's. Same to be said for most of the English doubles we all love; does that make it 'aftermarket' or just part of the service for a special ordered gun?...Geo
