Dust cover did not fit upper receiver without trimmming metal - Guntec USA AR-15 Upper Completion Kit w/ Gen 3 Dust Cover

I've bought a couple of parts from Guntec that I've been very satisfied with including somewhat higher-end AR15 handguards. I needed a grey dust port cover and forward assist and thought I would try a Guntec kit, based on the quality and exact fit of the handguards and barrel nuts.

The parts quality of this kit is top notch in terms of the precision cuts and the anodizing, but the length of the dust port cover was too long for my Cerro and Brass Aluminum made forged uppers (both companies make industry standard milspec uppers for others to brand and sell as their own). To make the dust port fit required trimming some of the metal from the dust cover and a small amount of metal from the frame of the port opening on one of the AR15 upper receivers. :(

I don't think I would try this Guntec kit again, because I know that Magpul, KAK and NDZ all make plastic dust port covers that fit and in almost any color you might need. Now getting a colorized forward assist is harder to come by, but I still think I will look elsewhere for upcoming builds.