Wow.. Ive never had any hardware missing on any of the hundreds of orders Ive placed for clients. That's some serious bad luck. I bet if you call magpul, they'll make it right.
Generally, depending where I get stuff, for the most part, the hardware is pre installed loosely in the corresponding holes, and I have to take them off-out before installation. On rare occasion, they're in a little bag.
Something's messed up there for you to not get correct hardware that many times, I would call and inquire and or politely complain.