Since my Comichron site was mentioned, I should clarify what it means. Both Diamond and Capital City, the two largest distributors in 1992, ranked Spawn #1 as their top-preordered comic book for May of 1992. They did not organize their rankings based on when comics actually shipped; in fact, there were many comics in the Top Sellers lists that did not ship at all, ever.
So it is very likely that Spawn #1 came out on that June date. The preorder charts would have still said May, even if it shipped late.
Diamond switched to reporting Actual Shipped Orders in February 2003, so in all charts thereafter, you are looking at when the book actually went on sale (with occasional exceptions, like AVX #1).
Wow! Hi John, thanks for stopping by. Can you shed any light on what day of the week new comics were being released back then? It looks like Thursday was new comic day in early 92, but by November of that year it had switched to Wednesday. I've heard from many people that Friday was "their" new comic day. Just curious. Thanks!