I've had a chance to really look at this rifle with magnification.
The stock has had no repairs. The nosecap and pipes apear to be original. The forward barrel pin is new. A little larger.
The barrel appears to be originally flint. No hint of ever having a drum. Just a well worn vent hole with some soft gunk inside. No hint that the barrel has ever been shortened.
The set trigger appears to be original with the set screw replaced. The front trigger has a sheen on the right side where the finger would brush it , but the workmanship and patina match perfectly.
The single lock bolt is a replacement , a common piece in any catalog, and the lock, the plate marked LONDON WARRANTED, is almost certainly so. In truth, the flintlocks on most rifles are replacements.
The signature is in script, but not readable unless you know what you're looking at.
Basically this is a very righteous rifle probably picked up originally without a lock or set screw in the trigger. It would make a very cool build for someone wanting something different than the usual E. Tenna. style of the same period.