Just because you own a firearm does not always mean you are free to sell it. One example of an illegal sale of a firearm without a license would be: Let’s say that a guy named Joe has a table at the local flea market and someone walks up to him and sells him a firearm for $75. Then Joe puts that same firearm out on his table for sale at $100 hoping to earn a quick profit. Joe would then be engaging in a firearm business without a license. A few years ago several flea market vendors found this out the hard way in the Tulsa area. None of this applies to the original post, but I figured I would bring it up after reading some of the responses.
If Joe puts it up for sale the next day, the next week, or the next year, then it's ok?