Those are AUX inputs. A different-colored (black, here) collar around a jack is normally an output; jacks without that are generally inputs. Except here, for some weird reason. Annoying.
Also, it seems to me that this won't exactly "acid" because it's designed to do a lot of things the 303 wasn't. Ratcheting, for example. Instead of that, I would suggest this: https://www.modulargrid.net/e/transistor-sounds-labs-stepper-acid This has the modulation outputs you want, plus it is...for all intents and purposes...an improved TB-303 sequencer with some extras. About the only thing it doesn't seem to have is a "random sequence" function (I might be wrong, though) to emulate the "take the batteries out" results.
The Metropolix is a great sequencer...but it shines best when doing Chris Franke-type sequencer manipulation. The Stepper Acid is a lot closer to what Larry Heard (aka Mr. Fingers) used on that very first ACIEEED track, "Washing Machine".