In Sheldon's weapon shop I can spend Gold Sheldon Licenses I got from importing my Splatoon 2 save to unlock weapons before reaching the level requirement. There's a counter that shows how many normal Sheldon Licenses I have, but how do I check how many Gold Sheldon Licenses I have?
From the splatoon wiki:
Gold Sheldon Licenses do not have a counter in the user interface. Instead, Sheldon will tell the player how many they have left after they make a purchase.
So I guess they expected you to just spend them real quick and move on, and didn't bother programming it in the interface.
If you use all of your silver licenses, the display will instead show the number of gold licenses you have. Since this is a resource limited to importing data from Splatoon 2 as far as I can tell (doing so only gives you 3 gold licenses and there is no other way to acquire them), it seems they did not assign much thought into having a good UX for displaying them.