I'm sorry haha, theres a slim chance they could be real but I don't wanna get your hopes up anymore , lets pray Oda will do something truly epic for Usopp regardless sooner or later, especially with Dorry and Broggy here now too ofc!
Usopps fans are so patient, kind and just all round nice from what I've seen, yourself included ofc so they deserve the best kind of payoff Oda can give them! Especially given how much hes neglected Usopp for so long ofc!
Usopp and Yasopp reunion will be peak fiction surely, nothing less!