I just talked to model 1...they have 16" lightweight barrels in stock, and you CAN get the gas block front sight base...it's the same one that's on their bull barrels.
My Model 1 kit was fine, the only issue I had was the quality of the charging handle. The rifle itself shoots fine, and I've had 0 problems with it...no FTFs, FTEs, nada.
The upper receiver has the same weird little mark on it that my RRA has, fwiw. Fit and finish are fine, and the upper mates perfectly with my Eagle lower...pins are a little tight, but that's good...no "play" between the upper and lower.
Looks like Model 1 can hook you up...I will probably be ordering a lightweight kit from them myself here before too long...probably to go on a Cav Arms lower.
Here's my current Model 1 rifle:
[img]http://img.villagephotos.com/p/2003-7/188491/modular1.jpg[/img]
BTW, the only negatives I've seen posted about Model 1 was me, about the charging handle, and someone else who ordered the lightweight barrels when they were out of stock. That happened to me, but I just changed the order to a regular barrel, and I had the kit in 3 days.