Rather than arguing about what is and isn't a zip code, here's an actual answer: no, at least on Firefox Android (and I assume generally on Android devices), if

Rather than arguing about what is and isn't a zip code, here's an actual answer: no, at least on Firefox Android (and I assume generally on Android devices), if you have "inputmode=numeric", then the only keyboard available to the user is the phonepad-style number keyboard, and they cannot switch to another keyboard. This honestly surprised me, my expectation was that it would select a keyboard by default, but you'd still be able to switch to other keyboards manually. So I guess if your zip/postcode/PLZ/etc field needs to accept international values, don't use inputmode=numeric (or similar) on it.