On-sale date from Amazing Heroes #31, with shipping date of 1983-08-23.
This issue is a variant of What If? (Marvel, 1977 series) #42 [Direct].
There exist further variants:
Letters from readers: David Allen, Sandro Bucci, John Burt, Andrew Walls, John A. Wilcox, R. Babb, Rob Marsh, Scott St. John, Dave McLeod, Matt Brett, Damon Stafford, The Watched