other than that - purely cosmetic (tail lights, grilles, trim, side markers, interior...) If it needs a new engine, you can throw whatever you want in there - regardless of what was original.
other differences
radio has knobs (68/69 thumbwheels), antenna (different size mounting hole), dash pad one year only ( 67 - 76 all interchange) Idler arm one year only, Gas tank one year only (single strap beteen frame rails)
Mine was a slant 6, auto on column, no console, with little options. Now it has a 71 340, 4 speed, AC, PS, pearl paint, cloth top, plush carpet and has 68 bucket seats, 69 hood and GTS stripe, 67 trim delete, 68/69 fender mounted turn signals, disc brakes
View attachment 172216
View attachment 172217
View attachment 172218
actually the value is more in what you think it is worth and what year you like best.
I like the 69 Dart the best. They had 3 years to perfect the car. Overall the style & trim is best in 69.
THIS IS JUST MY OPINION
The reason I have a 67, I got a deal on it and my wife liked it. Built the way I thought I wanted it.
There were about 3,700 67 Dart convertibles. ALL convertibles are GT or better (GTS, Swinger)
If you try to restore to correctness it can be harder to do with a 67 due to some of the one year only stuff not being reproduced.
I STILL HAVE NEW IN THE BOX LEGENDARY DARK BLUE INTERIOR FOR A 67 CONVERTIBLE FOR SALE
It seems there are several convertibles for sale. Don't know how many 68/69 were made but see more 67 convertibles than the other years. Was this because they made more, don't know, but if I didn't have my convertible I would be checking out the 69 convertible right here in the for sale section
If you like it and it is a deal you might want to go for it and built it the way you like