I been lookin for a TM seat locally for a year.
Ended up getting a RM250/125 1976/78 seat.
You get a plastic seat base.That dont rust or crack
Like the steel base.You do have to modify the rear mounts a
little or make new ones from alloy as I did.The cosmetic difference
is the Kick-up at the rear of the seat,I think it looks good.And the cover.