I bought a new set of "Magpul" BUIS from a top rated ebay seller (I know, I know) around Christmastime and just got around to installing them on my son's AR. Both bases cracked and I didn't really snug them down.
I asked for a refund or exchange and have heard nothing of course. I contacted Magpul and asked if it would be possible to purchase just the bases, the piece that the installation bolt goes through. I figured I could take them apart and back together with some help, and replace the bases which are are defective/cracked.

Magpul CS rep replied very courteously that they didn't make these sights.
"Based on the pictures you sent, and thank you for including those, it appears that those are not Authentic MAGPUL MBUS sights. I can tell by the mounting screw that is used. It is not the same screw that we use. Even though it is stamped MAGPUL USA on the head, the end of the screw is not cut right. Ours is cut flat and the one you have protrudes a bit. Also, the detent for the adjustment wheel is too far exposed."

So I guess I'm SOL. Moral: Buy from a reputable, brick and mortar or internet RETAILER, not ebay scammers, and buy the genuine article.

We're in the same boat, I got ripped off on a fake buttstock a few years ago.

Yep. Lots of fakes out there. The polymer sights are most commonly faked, but there even fakes of the fancier metal BUIS, like the Troy sights. I had a thread a year or two back in which I compared a genuine Troy to a counterfeit. I was sent the counterfeit in a trade from a long-standing forum member who had no idea it was a fake.

Yup. That sucks, but it's fleabay for a reason.

I just don't understand why plastic has to cost so much.

I guess there are levels of quality even among plastic bits. These sights seem functional but if you can't screw them to your rifle it's kinda pointless LOL

AirSoft types love them, lol.

1. How did you pay ??
2.,Have you contacted eBay ?

Go to your eBay home page find the item that you purchased, there should be a link to report seller/item. Even though you are passed the 45 day rule you still may be able get your money back. Counterfeit goods go by different rules with them. Chris

I haven't use ebay in at least 10 years for that reason, I only use reputable vendors and you know what they say if is too good of a price there is a reason.

I was going to buy a "Magpul" foregrip on eBay a few weeks back but the price was way too cheap (around $10) for it not to be a cheap counterfeit. I ended up ordering the real deal from Magpul for $40 and it's good to go.

eBay is flooded with Chinese junk knockoffs, that seems to be 80% of it anymore.

This is not an issue that is exclusive to ebay. I have, without a doubt, been sold counterfeit stuff via Amazon too. Caveat emptor!

Thanks for the heads up.
Mine looks legit, but I didn't think to check before now.

If you wait around for sales you can get good deals from AIM, Brownells etc.