I'm familiar with T mount and no, that will not work here as there is no over-mat, borders are exposed. This is a unique benefit show at this venue: these are small works that sell for $100.00 each, artist anonymous until after sale, and all proceeds benefit the gallery/museum.
Purchasers will be re-mounting if desired after purchase. So mounting should be reversible and secure. Is there double-sided linen adhesive tape?