Think there are all used ... least the ones I've dabbled in for both powder burners, springs, and PCPs - tested by the factory crew at some point during quality control. My most expensive PCP purchases were shot by the dealer prior me getting it ... came with little report cards too.
I'm not sure I've ever received a new rifle or gun.
Okay, no way the rule of the land, just my simpleton view:
Factory Quality Control - New
Dealer Opened Inspected - New Open Box
Dealer Tested - pressure, fps, tuning, shot group - Used
Returns, totally up in the air
Personally, I have less issues with "Used" guns because it seems the prior owner has vested interest to work out any quirks from the daily repeat processes at the factory and or vendor. I'm being very generalized here and applies to may products sold.