Hello and welcome to the forum. This is what I have found on these berrries.
Shepherdia (Buffaloberries) are a genus of small shrubs which have rather bitter tasting berries, native to northern and western North America.[1][2] They are non-legume Nitrogen fixers. The fruit are often eaten by bears, which by legend, prefer the berries to maintain fat stores during hibernation.[3]Buffaloberries are used as food plants by the larvae of some Lepidoptera species including The Engrailed (recorded from S. canadensis) and Coleophora elaeagnisella.
Buffaloberries are edible for humans. They are quite sour, and afterwards leave the mouth a little dry. A touch of frost will sweeten the berries. The berries can be made into jelly, jam, or syrup, or prepared like cranberry sauce from the forefrost berries.[3] The berry is recognizable by being a dark shade of red, with little white dots on them. They are rough to the touch, and found on both trees and shrubs. Wikipedia
As long as they are fully ripe and have had frost on them I don't see why it would hurt to give it a try. Since they are prepared similar to cranberries I would use a cranberry wine recipe such as the one in the recipe section of this site, and adjust it to how much you are going to make. Good Luck.
