I'll be taking my AR to The Gun Vault in High Point when my comp and 14.5" barrel are in. Spoke with Eric today, and he said pinning the comp/installing the barrel won't be a problem. They put Trij HDs on my HK P2000sk a week ago and did some work on my M&P a week or two before that.
Nice guys. I'm happy with what I've had done there so far and will be taking another HK for sight installation as soon as I can get a hold of a set.
After hearing horror stories about smiths boogering up HKs due to difficulty removing and installing the sights (I'm sure it's not just HKs, but that's the forum I was on), I was a little reluctant. Eric did a great job in 20 mins...very professional.