Right color or different scarred eye is one thing but Oda drew the Kabuto completely differently, not arguing just saying I think it's a safe bet he has more than one.
As for switching weapons on the fly, that has been Usopp's whole deal since day one. Rubber Bands, flash dials, egg ammo, pepper ammo, impact dials, fake hammers. It goes on and on so how does switching Kabutos not make sense?
@ Gerri, it speaks of Wapometal! Awesome forshadowing for sure!
I know its the "Black Kabuto" I just referring having multiple ones seem overkills. He developed a newer model nothing wrong with that. I also know Usopp has always switched on the fly, yet switching from Black Kabuto to 'Slightly off Pink Kabuto' to 'Lime Puke Green Kabuto' would sorta be a little overkill to me. Now switching from a 10 pound hammer to a 1000 pound hammer is a different story.