I'd say the best way to ensure authenticity is to check for the "made in USA" on the stems, and to check o-review for the SKU and match them up. It's also usually a pretty good sign if the seller has boxes and paperwork
Unfortunately he doesn't have any original packaging - he even mislabeled what they were, but the picture is very consistent w the O-Review description and picture.
Did the Gunmetal FMJ have the peeling and flaking problems?
I have the gunmetal finish on my Splice and they are pristine after 7-8 years of owning them. Granted i rarely wear them these days, but i did when i first bought them. I think you just need to take care of them. I would never put them on any hard surfaces without first laying down the microbag and i would wipe them down after each use to make sure there weren't any skin oils or sweat on them.
i have this exact pair sitting in my display case. Great color combo and the emerald lenses are nice looking. i wouldn't pay more than 80 for a pair thought. I picked mine up for 50 on ebay, like new condition.