I think we are of the same mindset. I recently acquired this old Rigby: https://www.gunsinternational.com/guns-f...un_id=102280015

It has a trapdoor grip cap and I opened it up to find some old deteriorated brown paper and a front sight with the bead broken off. It has a stock oval that reads 1 of 3 with the initials G.R.G underneath the initials is 1936. I emailed Rigby to get original info on the rifle and this is what they sent back:

Mauser Sporting Best, made for MRS L G CAINS. June 15th 1925. Weight 7 1/2lbs .30 Calibre 25 1/2. Barrel 14 5/8 inch stock. ivory bead trap in grip.
for 30 Calibre US cartridge

Everything lines up except that date and those initials on the stock oval.