If it works OK and you are fine with it, then everything is cool.
Myself I'd just be ticked that the scope was represented as an original (especially considering clones can be bought in the $40 range, not $150). If he says he gets them from the military, I would assume for the price that they had been used "in-country" and I would look for the abuse they would have been subjected to. Scratches, dings, dirty, etc. I haven't seen either an EOtech or Aimpoint on ebay that is being sold by someone that has been to Iraq or Afghanistan that wasn't beat up pretty good, with one exception on an EO, and it still had some of those present just not that bad.
You may be able to call Aimpoint to verify the serial numbers, but it sounds like the realization that you got clones has already hit.
If you can contact the seller, and hope he does the right thing. If not, you can always submarine him at the next gunshow.