yeah , i bought that issue off the rack , loved the Giant sized issues back then -more bang for your buck ... sold my GSXM for a couple hundred , it was well read
probably a 3.0 ,i pretty much collected from 1972-77 m and then sporadically untill about the mid 80's,... still have most of them except for the big keys ,.... but now there are so many keys that i probably have dozens of them that i didn't know about , i can't believe Spidy annual #16 is a key these days , it's just drek to me .. same with my Avengers annual #10 , figured it's worth a couple bucks ... nope big key now