If they are company property , (you got them from their warehouse, right), then they are not YOURS to sell, weather you still work there or not.
IF you go ahead and sell them you may find that your next check your waiting for may be minus a few figures.
Or worse, the company calls there lawyers about missing property, then you have to pay for them as well as any legal consequences.
Also, I'm sure the company has the numbers off the rec's you have, all they need to do is call D* and report them as missing and D* will shut them down, or not activate them when someone calls in.
Just because your checks are several weeks out, doesn't mean you own the property till then or that they become YOURS.
Either way, your better to contact your boss to verify what you have and ask them how to return them.
Jimbo