I did read that same report before I ordered mine.  Hopefully I'll get out to the deer lease this weekend and put a few rounds thru it.  I'll report back if I see any issues.  I purchased mine several months after that report was made so I'm hopeful it was either an issue just with his gun or has been resolved.  Since he didn't see it in the GUA5 he also purchased, I'm thinking it was probably just the gun.  I've only seen the one report of that issue.

I also have a mint 1978 SP1 carbine.  I've compared the 2 and the detent pin looks to be in the same position to me.  After hand cycling my action 30 or more times I see no marring of the face of my buffer tube.

I can say that the extension tube extends out about 1/4" more on the Troy than the Colt but I can't tell you if that's because it's longer or just not screwed in to the lower as much (sorry I'm not a builder), hence the reason why I wanted to buy a complete gun to begin with.

Earl

Video showing Troy's current retro product line on display at Shot Show 2017 made by Ian (YouTube InRangeTV channel).

YouTube: InRangeTV: Troy Retro AR Carbines

Ive been thinking about buying one of these and you're right, I couldn't build one any better than that, in fact I couldn't build one that nice. I like the old grey color and I think its cool they put an auto mark on the selector and made a fake auto sear pin to make this look as authentic as possible.
Very cool rifle and Troy did a GREAT job

I'd smash

I think Troy is on the right track and doing a good job, they are building some pretty close to correct carbines, packaging them in a nice way with some little extras, and pricing them right so they sell and some of the money even goes to good causes.  We all know there are a few things they could change to make them even a little better and more correct but overall for the price you can not do better.  Right now they are focusing on these particular theme and special mission type builds but personally I would like to see them build a nice affordable standard 603 to give Colt a run for the money at the same time allowing more people to enter into the retro world easier and then build something a little more complex like a 607 for the next level of retro lovers.

For some reason, the extra inch added to the barrel length bothers me - it's such a minor thing I know, but I'm anal about the littlest of details when it comes to .mil clones - primarily with aesthetics.

Fucking NFA bullshit...

Since you're 'anal about the littlest of details', is the front sling swivel held in place by a roll pin or a rivet.  The last I checked, Troy was using a rivet.