I saw your post and want to introduced myself. My name is Marty and was a friend of Glen's up here in Michigan for over 30 years.
He was the one who handed me his Thompson and said shoot it. I was a Recon Marine in the 70's and was lucky enough to play with a lot of weapons, but never a Thompson. Glen also helped me become a GM designer like himself, and invited me to the Second Chance Pistol event where I met the Michigan crew.
Over the years we have lost more than a few friends from the crew. Which brings me to writing this. Glen sold his Thompson to one of the guys in the crew (Jeff) along with his famous tackle box full of Thompson parts, including a separate box of parts, springs, mags, drums. I was at Glen's house in Solobury when the parts were exchanged and I thought I saw a 21 kit in the box.
Jeff is up north at this years Second Chance shoot. Once he gets back I will ask him to go through the parts and see if he has one of Glen's 21 actuators.
I have been to this site many time to read and learn everything I can. There are many knowledgeable people on this site. I also have many of the Thompson books (Tracey's, Frank's, military TMs, to name a few) but I learn quite a bit off here.
I checked Glen's WH Thompson blish lock slots for any damage.(we know his back end was cracked and welded), but will save that question for my next post. Thanks Marty