The original vinyl top fabric was thicker and had a more substantial base backing than what's been available for several decades. The current stuff is called "gause back", as the original was more like "canvas back". The grain of the fabric looks the same. I believe it should be "Boar Grain"? GM used the "Levant Grain", which was the finer grain. You can also verify the width between the flat "seams", for general principles.
Getting the freshest fabric is good to do. Chrysler OEM tops came in a box, folded up. After 40+ years of being folded, I somewhat doubt they'd flatten back out again.
In a thread on dual snorkel air cleaners for 1971 Plymouths, there's a link to the Hamtramk Registry. They have a page of icons for the Dealer Data Book and Color and Trim, which would have the swatch of the correct grain of roof, name and color. Plus LOTS of other information for each model year, up to 1979.
Getting a new top will make the car look much better. Getting it sealed along the drip rail pinch weld (removed and replaced) is something to ask about at the install shop. Plus making sure they use the best glue to keep it glued down (not bubbling p at speed). Plus what they plan to use as the underlayment prep of the metal and such. Might find some hidden rust in the quarter panel joints and around the rear window lower section when everything is stripped off.
CBODY67