I need to cut down on the beers Mage, but I'll be in touch.
Coblee, the BTC//LTC Addresses and Keys will be engraved on the coins, the mint could not meet the requirements unfortunately.
If a mint engraves the private keys on the coins, it's one more third party who knows the private keys...
Addresses are fine but private keys should really be handled by the less amount of people as possible.
Maybe you want to consider paper private keys instead.