Official Index to the Marvel Universe #13
2010
Note: The cover shown looks different than the solicits because this is the actual cover, not the solicited cover. As the series progressed, the writers ended up covering slightly different issues than predicted. The covers in this series include three reproduced comic covers side-by-side, each representing the comic in the series indexed. It had been the first issue of each series, but not for this issue. In this issue: Iron Man: Director of S.H.I.E.L.D. #28, Amazing Spider-Man #534 and Uncanny X-Men #495 are shown. Inside, the series begins indexing the X-Men at issue #490.
The Official Index to the Marvel Universe contains detailed synopses of individual comics, including all of the relevant data pertaining to the comic as well as a thumbnail of the cover art, 2 issues per page (roughly). In this issue, Mister Jeffries appears on the cover of Uncanny X-Men #514. Also, Northstar appears on the cover of the 2nd printing variant of Uncanny X-Men #511 and the cover of Dark Avengers/Uncanny X-Men: Utopia #1.
This issue also confirms Northstar’s identity in Uncanny X-Men #510, where he was shown in one panel, unnamed. It also reveals two previously unknown appearances of Mister Jeffries! One is Dark Avengers/Uncanny X-Men: Utopia #1, an issue already collected for Northstar’s appearance and the other is a NEW issue not previously collected: Uncanny X-Men #513, where he’s identified from the script as one of the characters in the background as a silhouette.
Silver Surfer Annual #1

What If? Secret Wars #1
During the portion of the story where Doom is defeating all the good guys, a super insurgency group of heroes assemble at the Baxter Building to oppose his conquering ways, led by a very pregnant Invisible Woman. In the foreground, just behind Luke Cage and in front of Hercules, you can see Puck, but since he’s facing the podium, away from the reader, you can only see the back of his head. A blue-ish figure in the lower left might be Sasquatch, but is more likely The Beast. 

Marvel Age #59
Well, that’s not so much fun, is it? Just business, but here’s some funny business: the calendar! The back pages of many Marvel Age issues featured a comical calendar with staff birthdays, one-liner jokes and parodies of various Marvel characters. The back cover of this issue had a calendar for November 1987 featuring cartoon Alpha Flight wishing Alpha Flight writer Bill Mantlo a Happy Birthday on the 9th. In addition to a missing balloon tail (there are six Alphans and five tails), the six Alpha Flight members shown are ALL WRONG! Remember that this issue was concurrent with Alpha Flight #55 and by that issue, the very man honored in this panel, Bill Mantlo, had made some significant changes to each of the characters:
Incredible Hulk #606
As seen in the inset from that panel, the image above is printed with a hint of the half-tone method of printing used back in 1982 for the original issue, and is a nice touch, though we’ve seen this nice touch used before recently in 


Weapon X: First Class #1

X-Men Forever #15
X-Men Noir: Mark of Cain #2

Fred Hembeck Destroys the Marvel Universe #1
Later, while Cap and Iron Man (Jim Rhodes at the time) discuss their situation while waiting to be processed in the afterlife, Northstar appears very tiny in one corner as a ghost.
This wasn’t the only sort of thing that dated the 1983 portion of the story, but similar to having Jim Rhodes in the armor, smart Hulk, etc., the changes that occurred betwixt writing and publication would have been obvious to the sophisticated reader in 1989.