Fitting 1968 Seat covers over 1967 seat?

[Powerslave]

I have a 1967 Dart GT that I'm cloning to a 1968, it has buckets which have the plastic back on them which was a one year thing I'm pretty sure. I like the look of the plastic backs but i also don't want to shell out a load of money and have to hunt for some 1968 buckets. I don't think they changed much with the back seat so I'm pretty sure you can put a 1968 cover over it.
My other option is to use the '67 interior (door panels are the only thing i would re use) but keep the '68 external appearance.

 

[RedFish]

67 buckets have vinyl laminated steel backs and dress shields. 68 buckets have a vinyl or carpet covered hardboard back and plastic hindge covers. As far as I know , the only problem with the swap is the missing screw holes for those hindge covers.

 

[Oklacarcollecto]

67 buckets have vinyl laminated steel backs and dress shields. 68 buckets have a vinyl or carpet covered hardboard back and plastic hindge covers. As far as I know , the only problem with the swap is the missing screw holes for those hindge covers.

I think this is correct also.