No federal or state (Indiana) laws prohibiting such a sale.
Local municipality may be another matter.
I did once buy a Daisy Red Rider BB gun from someone on GunBroker.
It was used, and the price was right. For $25 I thought it was a deal, so I bid and won.
Then the seller tells me he will ONLY ship to an FFL.
He wants to ship it overnight, and charge me $65 to do so.
I told him I would rather take a non-paying bidder hit than to pay that asinine shipping.
I told him there was no law governing BB guns. He argued that it was his butt, and he would not ship a "dangerous weapon" to anyone other than an FFL.
I got a local FFL to send the guy his info. and told the seller I would NOT pay overnight shipping.
He finally agreed to ship it for $20, but it still had to go to an FFL.
That FFL still tells people about my "dangerous weapons" purchase, and this was 8 years ago!
You shouldn't have any problems, unless you bought from the same seller I did.
Now I'll shoot house-destroying woodpeckers with a Daisy because my pellet gun isn't allowed.