A company by the name SEM makes vinyl and plastic sprays that work on interiors very nicely.
Their Camel color matches my interior very well. You cannot tell the difference unless you know where to look and look very closely if then.
I found a can a few years ago at my local Napa. But there are several places online that carry it for around $10 a can.
For reference here's what my interior looks like. I believe it is the Honey color, though AMC offered 4 different shades of tan over the years.
You probably won't be able to tell unless you look, but the drivers side seat pan I had redone in boat vinyl, and it didn't quite match, so I sprayed it with the Camel color vinyl spray and holds up nicely to years of sitting on even. I might touch up a few spots next year that are finally wearing through after 6+ years.