A new totally stock 1406 should work with minimal adjustments (all external), especially at or near sea level. It comes with a great user manual that explains each adjustment, as well as jet and metering rod adjustment/selection, if necessary. After you get the idle mixture and idle speed set, one of the most common issues I've found is an off-idle hesitation that can be resolved with 2-4 degrees more initial spark advance.
However, with a used carb, you never know what you're getting, regardless of seller description. It is very common for air bleeds to be semi-clogged and brass parts corroded. I say this having bought and sold 1405, 1406, and 1407 carbs for a few years. I can honestly say, I never bought a used one that was anywhere near as good as described. But the good thing is just about every one of them was totally stock, because those carbs are typically bought as "bolt on and go".
You can usually tell a used carb's condition by its appearance. If it looks shiny and new it's probably fine. If it's faded to gray, you never know what you're getting. You may have to disassemble it, soak the parts in carb cleaner overnight, followed by using wire and compressed air to clean & blow out the air bleeds. Then you may have to replace any corroded parts like jets.
As an alternative, Holley has an eBay store where they sell factory refurbished carbs. I have bought two of them over the years, and both were literally like new. Here's one that would work well with minimal adjustments, possibly including float level. If the link doesn't work, you can google "Holley eBay store".
https://www.ebay.com/itm/Holley-0-8...632054&hash=item418af91a00:g:SpUAAOSwU-pXvK-h
