The hinges #2 should be like yours but i think later ones have a stop bar added.
The problem is the early seat is drilled to take #11, and yours takes #28 and the bolt pattern is different. I assume you can make something to hold 28 on the bolt pattern for 11.
Then you can sell me your stock seat..
You get a hold of#11, and the latch assembly , it may bolt right on..not positive..
No locking seat then, but unless you are locking your helmets undrr the seat..no biggie.