A couple things here. You can swap out parts. But you would want to know if it's AR10 based, DPMS etc. One of the issues is the lack of standardization. You may run into some annoying issues. For example with most AR308 rifles a wedge is needed for MIAD grips due to the different shape of the lower and gap. $5 part but if you don't know... The mag release on most isn't the same size as AR15. So no swapping in a Norgon. The trigger however is easily swapped with AR15 in every model I've seen.
Once you get rid of the ugly gas block, the front handguard, the pistol grip, the crappy stock etc , trigger etc the price gets up there fairly quick. It's usually cheaper to just get one already configured how you want. Although this does present an interesting base for building off.
16" barrel. This presents it's own issues with 308. Reliability being the primary concern. KAC and LMT are the only 16" AR10 rifles I'd consider at this time. Most overgassing them. Even then KAC and LMT have gone with duel extractors on new enhanced or gen2 bolts. You don't see this as an issue with 20" or longer on the 308.
The barrel is a 16" 1:10 twist CL deal. Is this what you want? I prefer stainless match myself. But I don't use mine as lead hoses. The cost of 308 should be considered.
7075 is decent. Although the Armalite AR10 is 7175.
