Based on date it hit the newstands/comic shop ASM #252 is the 1st appearance, January 31st 1984. Followed by Marvel Team-Up and Spectacular Spider-man, both on Feb 14th, 1984. Secret Wars #8 is the origin story but didn't hit newstands/comic shops until August 28th, 1984.
Amazing Spider-Man #252 - http://www.mikesamazingworld.com/mikes/features/comic.php?comicid=48004
Marvel Team-up #141 - http://www.mikesamazingworld.com/mikes/features/comic.php?comicid=45868
Spectacular Spider-Man #90 - http://www.mikesamazingworld.com/mikes/features/comic.php?comicid=46937
Secret Wars #8 - http://www.mikesamazingworld.com/mikes/features/comic.php?comicid=48483
I think previews should not be considered 1st appearances unless they include a full story along with it. Marvel Age was a Black and Red suit Spider-Man prototype that was not used moving forward.