Yes, yes – I know this is obviously not the 1st appearance of the grey Hulk – but if you think about it, it actually is. While the Grey Hulk truly appeared in The Incredible Hulk #1 they had to change the color from grey to green and act as if that incarnation of the Hulk never happened. It wasn’t until 1986 when Al Milgrom decided to bring back the grey Hulk as if he always existed! So, while this is literally the second appearance, there is an argument to say that this is the first time the grey Hulk appeared with the intent to make him a new character.
1st (2nd) Appearance: The Incredible Hulk (1986)