I kind-of assumed it was set up to supplement or replace whatever minting facilities were already in place, not that it was the first and only mint for Republic credits. I guess we'll see.It appears to me that it was already operating as a mint, there are enough old republic credits in circulation that they are quickly recognised, and there is talk of official Republic ships being allowed through the barrier. And it’s secrecy was compromised.
Talking about hints, the Banking Clan was mentioned in this episode. If the Great Work was to establish some kind of Galactic Central Bank, then they would be top of the list of organisations wanting to destroy it.