It happened, Peter had a flashback to it in the backup story of when Harry came and told Peter he was "back". It was explained that Norman had Harry's body taken to Europe and put a fake cloned body in the morgue. Basically he saved Harry the way Harry saved Norman when Norman first "died". The Goblin formula didn't kill him but put him in a coma he healed from. I'm guessing Norman neutralized the formula in Harry after he recovered because he doesn't have powers anymore.
But Peter decided that after everything they've both been through, he was tired of the Parker/Osborn war with Harry (Harry doesn't remember what happened to him in his last stint as the Goblin) and figured if Harry wanted to be pals again Peter would go with it.