If OP hasn't confirmed or implied they have the 3080 they might get away with, but ultimately the company will have evidence OP at least received the unit initially and can follow them up from there. Whether it's 'right' or not isn't really relevant; if they can prove OP got the 3080 and is not paying for it, they can go after OP for at least the difference in cost.

There's definitely a chance OP can get away with it, but really you have to as yourself is it worth the hassle, potential extra costs and time? Maybe. That's not a choice for me to make, I just wanted to put out my perspective as someone who has seen situations like this unfold/ dealt with them personally and honestly it has never ended in the client's favour. If you want to go for being evasive and keeping it there's totally a chance it would work, and if not you can just backtrack and say you found it. Just trying to give the info that it might not be that easy