Our current filtering mechanism did not allow for plain emails as uids. Which is what can be done and some people do it.
To safely import keys where there is a plain email in the uid, we can make use of the new mbox import filter, that is available since 2.1.14.
With this we can change our filtering (through import & export) approach:
gpg < keymaterial inspection.
This will give us the exact matching key (through fpr) if there is a direct match on the email, which is all delegated to gpg itself.