Winchesters are notoriously lacking in serial number markings beyond the lower tang. If by chance you ever find one with the serial number anywhere else, you've got a real rarity!
The barrel tulip looks like what Marlin used on Ballard rifles. Might be a completely new barrel, or maybe a Ballard donated it's barrel to your Winnie? If you pull the forearm wood and find a serial number on the bottom of the barrel that doesn't match your Win. it could be a Ballard barrel.