I doubt most will notice any trade-off in accuracy.
That forged F marked FSB and the tapered FSB pins are only relevant if you’re building a flat top carbine with the traditional front sight.
Have an A2 style or other non-collapsible stock, or otherwise happy with the one you have with no plans to swap it out?
Then don’t even worry about the MIL-Spec sized receiver extension.) The point is, there are plenty of excellent, high quality AR-15s put out by great manufacturers that lack more than a few of the MIL-Spec features listed above; some are even used by major US Law Enforcement agencies.
Consider it a starting point for your own research, certainly not the answer.
DPMS, Defense Procurement Manufacturing Services – Founded in 1985 as precision machine shop producing MIL-Spec parts for the Government.
Sure, many of the seven MIL-Spec traits listed above are nice to have – some certainly more than others.
(MPI and pressure tested bolts and barrels are nice to have, especially if taking your AR-15 to carbine class, where you will fire thousands of rounds, potentially at a high rate of fire, in a short time period with little cleaning between firing.
I have no personal experience with a Freedom Group Bushmaster.
I can tell you that my Remington 700 CDL is outstanding in fit and finish, and quite the tack driver. When it was time for my decision, I feared company integration, retooling and retraining challenges, so Freedom Group owned Bushmaster didn’t make my short-list.