Lose air horns and choke being out of adjustment is part of a basic tune up. At least it is to a good mechanic. Even back in the day I knew "mechanics" that did not own or know how to use choke angle gages. I lost count on customers that came back to the dealer and told me the car has never run as good as it did after a tune up.

Everyone always picks on "stealerships" but all I ever did was follow the normal process for a tune up. I have seen a lot of other garages just replace plugs and fuel filter maybe cap and rotor and call it a tune up. There is a point when a block heater is needed and GM described that in the owner's manual. That was mostly for our brothers in Canada and Alaska. Other than that carb will work fine if it is working as intended.

I know we think of Carbs as old but even in the 60's if a CEO could not get his Caddy started on a cold morning he would drop the brand and fine something that worked. This extended to all GM lines with a few exceptions for hi performance applications. I don't have personal expearance but I was told even new the 302 Z28 and the 375 HP big block could be tuff to get started on a cold morning,

 

Well I can tell you I have no idea about Choke Angle Guage. But the trick I learned with my old Mopar is 1/8" drill bit set it in the choke close butterfly and set it so that the bit will slide with a small amount of resistance, and not drag. Works like a charm.