Yes, it's not yet supported, but tokens that still have the mint baton will eventually be able to mint more.
Is there a way to do this outside of Memo right now using something like Electron Cash?
I think most SLP wallets support minting additional tokens. Surprisingly not many people have asked for it on Memo so it hasn't been a priority.
Also, would you know how to import the Memo private key into Electron Cash SLP?
I don't recommend loading the Memo private key into other apps, but it is possible.
