Hey Mike, it's John in reply - The Interstate tank is one I found on eBay and sprung for. Off a MK3 and there was some rust for sure. Sent it to
Metalworks in Eugene OR where they dip to first remove all paint and interior coating, then dip for rust removal, then finish dip with temporary protectant. It's in pretty nice shape now and I will paint it a very deep green with gold pinstriping.
Just FYI the seat is from Vietnam, from a company called Texavina - see their Interstate seats here:
https://texavina.com/commando-interstate-750-850-1972-1975/. The saddle is nicely stitched and the seat has nice foam/gel padding interior. The entire plastic seat pan however is rectangular so you don't have the nice rear curve to a rounded point as you see on the Corbin Gunfighter and others. It employs the side bracket setup and unfortunately you cannot drill this seat pan for swapping to a Corbin as the mast lock on the Corbin fixture will poke your rear end right through the padding - not the kind of room you get with the traditional Interstate OEM seat with this modification.
I am a fan of the bump seat with Endurance-style tank look which you may see via the links below. I am going to put together a separate thread on all of the research I've done on configuring a bump seat with Interstate. I spoke with Corbin and with Matt as well as several folks on the BBS and the nicest result is working with Corbin after you have chopped your Gunfighter / Smuggler seat for fit to your specific Interstate tank. I have done upholstery work so I have a Wanted ad in the Classified for a Corbin seat to perform the work.