Did They Make Square Bore AVS Carbs Made That Only Had The Small Bolt Pattern On The Base Plate?

No AVSs that I'm aware of, but AFBs did up until the mid '60s on big blocks and until '67 on the 273 Commando/Charger motors. Some of the late '50s/early '60s 4 bbl. and dual quad Polys used them too, I believe.
Moparlouie has a current for sale ad for some of the 273 carbs, for reference.
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[FOR SALE] - Carter 3853s carb
As you can see, the front right still has an inner and outer hole for some reason; but they aren't dual-pattern carbs.