I had a shop for a long while thru the '80's and early '90's, when it was still ok to work "by appointment". That is not the case now, and you have to have a legitimate store front.
The really funny thing is, the GCA 1968 was written in such a way as to specifically protect the "kitchen table" type of gun shop. The very thing they have morphed the law to deny?
Unless you are serious about opening a retail gun outlet, I'd advise against getting a license. You might get away with some other arrangement for a while, but inspections are often now, whereas years ago, they were infrequent or never. Once inspected, if you're not following the rules to the letter, you'll be revoked. It's really not worth the hassle, and that's what they want.