It does look like a muscovy. It doesn't have much caruncles but it could be young or a mix. If you heard this one quacking then it has to be a mix as muscovy don't quack.
They had some mallards and pekins at this little farm we went to also.
I'd really LOVE to have some Rouens since they look like Mallards but don't fly, but I already have 8 Pekins and no way my husband is letting me have anymore!
LOL