No it's not... Program files and settings are stored in two completely different folders... Even uninstalling a program shouldn't remove your settings unless it asks you first.
Well, yes, it will keep your Firefox profile and its related settings. It's only the about:config settings that will be reset, which I think is a sane default.
If you disable update via policy (which is the only way you can do it now that about:config method is removed), then going to "About Firefox" doesnt give you any options regarding updating.
I did check them. I set my settings to "Check for updates but let you choose to install them." via the about:config method, which is the setting I assumed they were referring to.
I could still update from 72.0.0 to 72.0.1 from the About Firefox menu item, and from the about:preferences#general page. I'm running Mac OSX Catalina.
That said, Firefox is definitely doing what they can to make users keep auto updates on. I do think there should be a way to manually update if you've disabled both auto-updates and their update checks, without requiring the user running the installer, forcing you to toggle one of those settings off again.
You can still manually update by hitting "About Firefox" in your menu, which will keep your settings as-is.