The school tweeted a photo of players opening boxes of limited-release shoes and other gear, hours before the Retrievers' unprecedented tournament run came to an end in a 50-43 loss to the Wildcats.
Although UMBC said the shoes were "unreleased" in its tweet, the Curry 5s were available via limited release Wednesday.
Both UMBC and Curry are signed to Under Armour. Under Armour's six-year deal with UMBC expires this year, while Curry is signed to the apparel giant through 2024.
Sources told ESPN's Darren Rovell that UMBC does not receive any cash for its deal with Under Armour. UMBC gets discounted prices on shoes and apparel in exchange for wearing the Under Armour logos on them.
Before the Retrievers' 20-point win over the Cavaliers on Friday, top seeds in the men's tournament had amassed a 135-0 record against No. 16 seeds.