Early Iron Man artists

[MikeRickard2]

I have a couple questions about artist Don Heck and his work on Iron Man. I've been reading my Marvel Masterworks reprinting the first twenty something issues of Iron Man in Tales of Suspense. i'm not sure if it's the reprint quality or the artist but there seems like a big improvement in Don Heck's art from volume one (Tales of Suspense 39-50) to volume two (Tales of Suspense 51-65). His volume two stuff (stories like the first appearance of the Black Widow and Hawkeye) is impressive. It seems more detailed. Here are a few questions:

1. Did Don Heck have different inkers in volume one and volume two?
2. Did Steve Ditko design the red and gold armor that followed the yellow tin can armor of the early issues?

[Digifiend]

Your copy of Masterworks should have the answer to that... there should be credits on the first page of each story.