Only buy your Troy accessories from known, reputable sources.
Gun shows, Armslist, eBay, Gunbroker, etc. have become rife with fakes.
To help out others on the forum, I figured I'd document a counterfeit Troy rear sight that I recently ran across, and compare it to a genuine Troy rear sight.
In the photos at the end of the post, the FDE rear sight is fake, and the black sight mounted on the rifle is real. (Sorry for the poor quality photos, but I was trying to take them on a grey, cloudy day with waning light, and I didn't have time to remove the real Troy sight from the rifle.)
The person from whom I got this sight apparently didn't know that it wasn't a genuine Troy. But having experience with real Troy products, I knew immediately that it was counterfeit. (And not even a good one. There are more sophisticated fakes out there.) The owner of this fake now has a set of known genuine sights to use on their rifle.
Here are the differences that I noted:
1) The fake sight feels cheap overall. The parts on the fake are cruder, and things like the lock button and the windage knob have noticeable differences in size and shape when compared to the real deal.
2) The finish on the fake feels rough to the touch and scratches easily, revealing the bright metal underneath. The real Troy is anodized aluminum with a fairly smooth feel.
3) The movement of the fake is gravelly, including both the rotation of the sight itself, as well as when depressing the button to unlock the sight once deployed. The real Troy's movements are smooth and the button is more easily depressed.
4) The fake wiggles freely up and down when it's stowed down, while the real Troy is held in place with an audible click and a little bit of passive retention when it's stowed.
5) The font on the body is different, and the markings themselves differ. The font on the real Troy is bolder and whiter.
6) The fake sight has two prominent silver detent bearings at the hinge where the sight pivots, as well as one prominent silver detent under the flip aperture. The real Troy uses a black rectangular detent on the sight pivot, and the detent bearing under the flip aperture on the real Troy is practically invisible.
7) The flip aperture on the fake flops around with no retention, despite the obvious detent bearing. The real Troy's flip aperture clicks solidly into place in either position.
8) The windage adjustment screw on the fake simply rotates freely in either direction, with no stops or clicks. The real Troy has solid, audible and tactile clicks every 1/10th of a rotation when the windage is adjusted.
9) The fake has no windage hash marks on the back of the sight.
Comparison photos below. (Again, the fake is the FDE sight):
To reiterate, only buy your Troy accessories from reputable sources