A J-Series Vehicle Parts List [book] for '65 is prob best starting point.
I have a '64 here.
It lists three colors Sylvan Green, Nordic Blue, Amber corresponding with
a three number Trim Code. This appears to be the trim color and level. I don't see an exterior paint code or paint/trim plate illustration.
A old school body supply and auto paint place can prob help - although they might have to mix a couple of samples in laquer.
'65 Brochure is promoting the new color options, so there must be dealer info available from both sales and service literature.
For example see the '66 Wagoneer brochure posted in here: