I am NOT a Minnesota attorney, so I'm not at all familiar with the case law. If you're really interested in going forward with this project, the art gallery almost certainly DOES have an attorney, and they should consult with him, for their part of the transaction; you, on the other hand, might consider consulting a separate attorney, since the gallery's attorney does NOT represent you.
That said, a quick search of the Minnesota statutes reveals under Minn. Stat. § 340A.301(d) that "Nothing in this chapter requires a license for the natural fermentation of fruit juices or brewing of beer in the home for family use." A quick search of the relevant case-law revealed nothing. (By quick I mean five minutes, really, if you want legal advice, hire a Minnesota attorney!)
The plain language of the statute indicates that in order to legally permit anyone other than your family "use" your beer, you will need to obtain a license, and thus no, you are not permitted under Minnesota statute to hand out samples of your beer to non-family members without a license.
NOTA BENE: they may be permitted to hand out samples without a license, but that does NOT mean that you are permitted to GIVE them the samples, so even if there are no legal problems on their end, there may be on yours. Obviously, as home brewers we all tend to take advantage of the fact that our respective state governments have better things to do than stomp on us, but if you're even a little bit concerned, definitely check in with an attorney. Alternatively (and cheaper) call your local state representative, and ask him/her for a candid opinion.