I don’t know. There doesn’t seem to be much used ADSB stuff on the market. Either way I can either submit a receipt or a copy of the 337. The 337 wouldn’t provide any determination as to whether the equipment installed is new or used.
I finally did circles inside the class Charlie and passed the test. Went to the correct URL and submitted successfully. All seemed good until I received email saying they want to see my receipt for the equipment before they pay the $500. I notice the rebate FAQ page mentions they might ask...