No, they were partially hydrogenated soybean oil back in the day.
Palm oil is thick at room temp, like partially hydrogenated oils are.
> Were oreos always palm oil or were they lard back in the day?
They did use lard till mid 90s.
https://news.cornell.edu/stories/2008/02/getting-lard-out-ko...
The fracking industry has made guar gum too expensive to use as a food emulsifier. I know someone who reacts to xanthan gum (which has all but replaced guar) and she's not a happy camper, because it's in fucking everything.