Not understanding what u mean by updates. Talking about body styling in the first generation? I thought each generation has minor body changes before it was changed to a different platform/generation? Sorry if I missing the point.
I wouldn’t classify them as minor. A 71 mustang looks very different compared to a 65 and they’re in the same generation. You have the 65/66, 67/68, 69, 70, 71-73. All body changes in the same generation.