The part number for the later ones from Moog was K7068, but they've been discontinued for about 5 years now.
I'd be surprised if you can order those from O'Reilly and actually receive them. If you actually found a set at a store you can lay hands on you should buy them.
The 73-76 cars use a different strut rod bushing than the 67-72 cars, they were thicker and the strut rods for the later cars were slightly different, the shoulder to retain the bushing was moved to allow for the larger bushing. Effectively with everything installed it was the same length as the earlier ones as far as the K frame to LCA distance goes.