what is U# and E#? What catalog do you use?
however... your concern is appreciated. but it really doesn't matter. in fact lots of coins here
use a different code-system because they're not listed in world coins catalog with KM# numbers.
take a look at older german coins for example (often using C# numbers), or countries which are not
listed in WC catalog (using a Y#, then changing to a - often different - KM#).
Or especially ancient coins having their own code-system.
Just use them - and add further information and numbering to existing emergency coinage if you like.
that would be appreciated since only few if any of the team members have access to such catalogs
if coins share a code-number you might even add a NOTE to the description field.
