I had a Jaeger made 1730 & we examined the wooden trigger guard with a magnifying glass & light & it was determined it was carved out of the stock. Were we wrong?
Maybe or maybe not. Ron Scott may have some info to offer here, or Chris Immel if he still checks in now and then.
Phil Ackermann had a little French boy's rifle many moons ago that was pretty much entirely carved out of wood; wood buttplate, sideplate, pipes etc. We thought the guard was also carved out of the same piece of wood, but it could conceivably have been a separate piece very tightly inlet and glued in place. I really don't know. There definitely was 'glue work' being used in conjunction with these wood guards and I haven't seen enough of them to offer any kind of definitive statement.
On the piece I illustrated, I used a piece of unstained hornbeam to make a sideplate (it looked almost like ivory or maybe boxwood) and a nosecap but I did carve the entry pipe out of the stock itself. It was done as a half-stock smooth rifle, very German but with a cruder American twist, some upper Bucks or Lehigh influence. Very much an 'imaginary' piece.