Rear engine door

[Beesme]

I just bought a rear r&m fiberglass door that came off a 78 buffalo . The height is right but I think it is slightly narrower than my 4106 . Do any of you know for sure ? The steel work is rotted so I ground rivets and removed . So of course I am going to grind rivets off my door . Well I guess the question is.I'm probably gonna have to fill edges to fit and don't know if I should wait till end of season . Uno a time thing ! Thanx for any thoughts!