let me sum it up real quick, im too excited for gammer in the morning, but this is everything ive ran into, or seen so far that is oldschool.

Geckos
SOUNDTRACK FROM FALLOUT 1 and 2!
mention of THE HUB
NCR
super stim-pack
Marcus, and super mutants from masters army. (with the weird lip hook thingys)
followers of the apocolypse
on the 5$ ncr bill during the loading screen you can see "Aradesh" the father of "Tandi" the first president of the ncr.

brb i think theres more

Well it's all canon. And you ARE in the core region. Plus it is obsidian! The ones who did FO1 and 2. I'd be surprised if there was nothing historically canonical in the game

Quite a few more I've stumbled across. Two I remember off the top of my head (other than some of the ones you named) are:

the town of Modoc is mentioned
Rose (and her yummy DeathClaw Omelet)

There's a chick commenting on crashing the vertibird near Klamath

cool, well lets keep this thread up. i find it uber interesting. Even tho i started off playing fallout 3, i still loved fallout 1 and 2 just the same.

Ok, i saw the woman who talked about kalmath, HA im suprised she didnt mention anything about a yellow keycard.

The Nitekin and talk of masters army is all pretty cool.

More stuff: The combat armor from fallout 1 and 2.
http://misc.thefullwiki.org/Combat_Armor_(Fallout)

The enclave Advanced power armor as seen in fallout 2,
http://ui10.gamespot.com/1961/fallout2_2.jpg

Klamath bob, who talks about a tribal from arroyo who caused quite a stir, but it was before his time.
(as well this reminded me of the children in klamath... so anytime i come across children in freeside i check my inventory)

THAT GUN = .223 pistol fallout 2
http://www.nma-fallout.com/content.php?page=223-pistol-origins

Don't know where I got it, but THAT GUN just appeared in my inventory one day...

I believe its baught at the dinosaur place. However its not a strong dps wise as the weatherd 10mm pistol.