Using FE's values, there is a .3% chance that they are C7AE-A
but that .3 percent would have my money on it.
I have never seen a C6AE-A. I would expect D2TE-AA as a factory head, C8AE-H or C6AE-R as earlier common heads, or less common, but possible would be C7AE-A
The C7AE-A would be a small runner intake like the rest, also unibody/truck design, more common on car 390s, and also correct on 67 GT500 Shelby, but don't get too excited, they arent a performance head, its just what was used on the 428PI of the day and has no performance benefit at all, and only more value to collectors if the date codes match someone's restoration.
70 Sportsroof, 427 FE/489 cid, TKO-600, 31 spline 4.10, A/C. modified Mass-flo EFI/CnC ported Victor.