That configuration is substantially similar to a great deal of M16A4's and M16A2's still being fielded after all these years. The only exception is the NSN'd M4 buttstock conversion kit 1005-01-569-6938 doesn't supply Magpul parts - it's just the generic M4 stock. The only practical difference in the buffer weights from an M16/M4 perspective was cyclic rate as already mentioned. Since the overwhelming majority of M16's in existence are 3 round burst, it's not significant.
Having an arms room guy that is paying attention to things like the bolt lugs and magazines, and is happy to replace old buffer springs/provide new magazines really solves 99% of the issues we see with M16's in theatre.