A couple more holley 1920 questions

That hole in the carb base looks totally bogus. There should be no place for unfiltered air to come in like that for an auto application. It does not look a normal location for a port, and that is evidenced by no support casting around that area. I will venture to guess that somene added that to try to tune the carb, or it is a manufacturing item that gets plugged and the plug fell out.

The hole in the plate looks legit.