Maverick said
Well now, I’ve never heard it called a “Rivet”. Not exactly sure what the factory term is.

Have you tried taking off the upper guard?

If you decide to, you should find on the rear of the guard where there is a large u-shaped retaining spring that fits into slots on the bottom forearm. Said spring is held into the upper guard by two lugs that go into the wood.

There was a guy a while back selling reproductions, but hadn’t seen them in a while. You might take the guard off and have the retaining spring copied by a machinist.

Sincerely, 

Maverick

  

Thanks Maverick. I don’t think I’d personally attempt to remove the upper guard myself but I have a gunsmith who’s going to look the rifle, maybe he will. 

I saw the post where the gentleman was selling reproductions but he posted “all sold out”.