That rifle looks to be a very early NA gun, probably dating back to when Jackie Brown was building for Phil. That'd be before Terry and I were involved as gunbuilders. Terry and I both built guns, and I did all the custom woodcarving and engraving.
Guns like that built when Terry and I were involved would have had the trigger guard pinned, not screwed (unless it was historically accurate to do so) and the finish would have been hand rubbed boiled linseed oil. Pull the tang bolt--if it's a wood screw instead of a bolt threaded through into the trigger plate, it's definitely not one either Terry or I built.
None of the NA guns Terry and I built were signed. We did build the full run of 250 Ferguson Rifles. I built about half of the ones that went out, Terry did the other half. They were a PITA to biuld compared to the rest of the rifles we built but they were pretty cool to shoot, though.
As far as knives and such, it's only my early work that had the engraved ECH III. Then I went to an round intaglio stamp that had my initials on it, and I currently use a rather rectangular intaglio stamp that has a stylized "H" on it.
BTW, the trek John Curry, Steve "Butcher" Welch and I did that y'all are referencing happened quite a few years ago. It was a blast, for sure, especially when our shelter collapsed in the middle of the night after a storm and soaked us (especially John).
I'm still kicking, I live in Roanoke, VA now and have for the past 8+ years. I still do some blacksmithing, but these days it's more as demonstrations at a pioneer village set up in Wytheville, VA rather than as a serious sideline like I used to do. I am currently involved with helping the city set up a blacksmith/gunsmith shop as part of a local museum project, though, which should get me more active in that regard.