No worries. It’s good to have an easy answer sometimes.
I see that you’re wanting to put states into the choice list? States will work but you mention zip codes as well in your use case. It’s prudent to mention the maximum of 128 items in a choice list, which won’t accommodate all zip codes so I’m assuming you’ll figure out zip codes in separate metafield or elsewhere entirely.
I’m not sure I fully understand the use case but, yes, a Metaobject is exactly how I would remove the need to re-create a list of items multiple times to assign to different metafield definitions.