Well I know that the '69 'Cudas was done by AMY as well as MPC..... The car I have in pieces missing the bumpers and grille is a older AMT kit.... Which if my memory serves me right that tooling that kit was made from dates back to the MPC days!
NOW, as for the '67 the '68 and the '69, the grilles are all different right? So the inside contour would be different! As for that is the hoods different (I REALLY don't know!) BUT if your talking about plastic models, I can't see why it be difficult to make a master copy from an existing part and make the body fit it.... Just me and how I customize/master copy things....
67/68 the upper valance was the same stamping on the real car. On the 67 they put plymouth in individual letters across it. 68 it was smooth with plymouth lettering on the left corner of the hood
The grille surrounds and headlamp doors on the real 67/68 were similar enough that pieces can be interchanged with minor differences such as screw mounting holes etc .
The grille centers on the 67 were a metal eggcrate type pattern, with one type of turn signal lens, the 68 used plastic grille inserts and lenses of a different design.
The 67/68 used the same hood stamping, however both years has their own design metal inserts on the hood. 67 has real thin fins, 68 used a pattern of chrome, argent silver, black and fake moulded in allen key bolts.
The 69 used a smooth bulged hood with no inserts, that was later recycled and used on 73 to 76 darts. As such its upper valance fits this hood, and its grilles are shaped differently.
I think you could use the 69 model, shave the side reflectors, and add in 68 style round side parking lights. Shave the bump on the upper valance to use the flatter 67/68 hood. I think the 67 grilles could be used and with your talent you could make a mould to make 68 style grille inserts, and 68 style hood inserts. These are not as intricate as the 67 ones. The emblems and fishes on the sides of the fenders are similar for all 3 years and about the same locations. If modeling the 69 as a 68, shave off the lower valance reverse lamps, as these are not on the 68. Taillights will be a bit tricky as you can find 67 lenses and 69 lenses. You could probably use the 67 lenses and reverse the colors on them. Use red in the centers, clear around the perimeter this would make them look more like 68s.
