last I checked, the Community Lot Skilling mod requires Open For Business or later.
is there a base game equivalent?

Found you this thread that confirms the MATY version won't work either.

Just so others know what else I found that doesn't work (not trying to be negative, just trying to save duplicated efforts):

Squinge has several versions of community-lot skilling (I personally prefer his to all others because his allow for only your selectable sims to gain the skills while out, not anyone else who shows up on the community lot---I don't really like maximally skilled townies who got that way by just showing up, and I do have objects across my various community lots that would make this possible for every skill). However, Squinge's lowest version seems to require Uni.

Wait, that makes sense---it was only in Uni that any sims (YAs) could gain skills on a community lot, right, in the game as shipped? So maybe that's why it isn't possible in only BG?

both links are the same.
were they meant to be different?

Yes they are, I don't think it was intentional..
But here are Squinge's mods.

Indeed, as Rosebine guessed, that was a copy-paste error. I've fixed my second link, which now points specifically to Squinge's lowest version of his community lot--skilling mod, the one for Uni only.