I've had really good luck buying used gear off eBay but every once in a while you get burned, it's bound to happen. Some brands seem to be especially rife with knock-offs - I know that in cycling there are a lot of counterfeit carbon parts (3T, FSA, etc) floating around, and apparently there's lots of fake Oakley sunglasses, frames, and lenses too.
Hopefully the info below will help someone else avoid my mistake.
I recently bought a set of "guaranteed authentic" Oakley frames off eBay from a reputable seller for my extra Radar Pitch lens, to save wear and tear swapping out between my Red Iridium Path and Black Iridium Pitch on my Grey 30th Anniversary Radar frames.
The first thing I noticed was that the new clear frames had the same plastic throughout the frame, whereas my grey frames have a different plastic for the nosepiece which allows you to squeeze the nosepiece together to aid removal and insertion of the frame.
The only marking on the frame is 9016 in the photo below, which hasn't turned up any info on Google. The earsocks are marked with the Radar logo, which seems legit, but the rubber feels different (less sticky) than my authentic Oakleys. Also, the nosepiece mounts differently (it slides directly onto two posts, rather than being hooked around the "T" on my real frames).
When I tried to install either of my Path or Pitch lenses in the new frame, there was no way it was going to fit. In the photo below, I've compare the fit with just the sides of the lenses hooked into the frames. As you can see on my authentic grey frames, there's very little gap to the nosepiece, so the lens can be guided into the groove easily, before snapping in the nose piece. On the new clear frames, the gap is absolutely massive and there is no way the lens will go into the frame groove.
Anyway, any insights are appreciated. Hopefully I haven't been ripped off. I'm not an Oakley expert by any means, I don't know what older model frames are our there or what's normal. I'd say there's a pretty good chance these are fake, though.
The answer from an Oakley expert?
Real Radars have a pin
in the hinge, not a screw.
A lot of fakes use Phillips screws and also write Oakley on the nose bridge when it's not supposed to be there.
Well, that explains it. I filed a Paypal dispute and got my money back, but now I'll know to check the hinge, and if there's a screw instead of the pin that authentic Oakleys use, I'll pass.