Stripped screws - Meprolight MEPRO FRBS - Self-Illuminated Flip Back-Up Rifle Sights

So these sights are basically tritium lamps inside FAB defense polymer flip up sights. I really do like them but the reason I gave them 3 stars is because I bought 2 pairs, so 4 sights, and 3 of the 4 screws stripped when I was tightening them onto the rail. I ended up fabricating my own screw and nut to fit them but that's crazy... I would have been pissed if I paid full price but I got them for almost half price with coupons and sales. In the end I got them to work and they're serviceable but come on, are the screws made of polymer too? That's ridiculous...