Certainly that is Tweety and Sylvester #1 but Sylvester has appeared prior and as early as FC 271 on the cover. Wikipedia only discusses the comics with Sylvester on the title showing 406 as his first comic. Technically true but not his first appearance which in comcland is all important. Still the #1 is such a good cover of both characters and a 9.4 is pretty awesome.
Anyway, His first cartoon was in 1945 Life with Feathers where the cat is unnamed and the bird isn't Tweety. Tweety Pie is probably the first real appearance of both in 1947 but Tweety fist showed in a 1942 cartoon. I can't remember if he was named but he did utter his infamous line, so it clearly is Tweety.
The other interesting thing about many of these funny animal comics is that the first appearances are so unknown and uncared about. The general population might put Tweety and Sylvester or Yosemite Sam as in the top 50 most recognized cartoon figures but in comic land, they get no respect. Disney has all the minor characters broken out: Beagle boys, Gladstone, Gyro etc. Overstreet can breakout Archie Pureheart, Sabrina the Witch, or Little Max and many others. Yet it forgets about the Warner Brother cartoon characters???
Seems weird that's all.
Add Tazmanian Devil, Speedy Gonzales, Granny, and the Orange Monster to the mix of first appearances I'd be interested in.