While you are on the site, in your browser find and click "Add to Home Screen" A CGN beaver app icon will then be created to your phone that is directly link to the site.
Note: This feature may not be available in some browsers.
I'm pretty sure you'd be okay. I have uppers from Yankee hill, Rock River, Armalite, and Vltor.....Troy rail fits on all of them. The only reciever I've got that a Troy Rail doesn't fit on because of those tabs, was a billet reciever made by Alberta Tactical.