Like the SP1 These have "slab side" lower, large front pivot pin, full round late SP1 carrier with C marking and exposed firing pin. Unlike the SP1 the MPC marked bolts have a space between the M & P, they also have blue extractor buffer, A2 delta ring, A2 flash hider/peel washer, A2 port door, A2 grip. SPII rifles also have the A2 barrel, handguard, and buttstock (save the Carbines).
301011 SP1 upper, shiney handguards
304436 SP1 upper, shiney handguards
310955 forward assit upper with large A2 plunger and CH forge code, shiney handguards
311XXX forward assist upper with tear drop forward assit
313XXX SP1 upper, shiney handguards
317788 forward assist upper with tear drop forward assit, shiney handguards
3212XX shiney handguards
327XX forward assist upper looks to have the large A2 plunger
339XXX CARBINE, forward assit upper with large A2 plunger CH forge code and shell deflector
339714 forward assit upper with large A2 plunger CH forge code and shell deflector, looks like it has matte guards
3476XX CARBINE, A2 upper with large A2 plunger CM forge code, fiberlite buttstock
354569 forward assit upper with A2 plunger CH forge code and shell deflector, looks like it has matte guards
Is this the difference in the 2? (SP1 and II)
Were they sequential in their production and simply model year improvements?
I'd love to see some more owners offer up their variants, so there can be a respectable sampling to add to the database
The more the merrier
Far as I know "all" (never say that with Colt) SPII's had those features, which were different then the SP1. A2 grips were used on some late SP1's though.
The SPI and SPII series used up old parts that were dropped when the M16A1 went out of production, and M16A2 production ramped up. This process took a few years.
Yes, we need more examples, the earlier the better.