I was hoping Cody would see this and respond. The importer will import credit card numbers into their own payment accounts, but I am not sure about tokens.
If you are using CDG Commerce, but are storing credit cards locally they will be imported locally and you can use whatever merchant payment gateway that you want.
The Stripe module works for both local storage, and remote storage of card numbers.
I believe if you import, use Stripe, and have stripe set to offsite (token) storage of cards, these imported payment accounts will just work.. though they will not be converted to token based. Then, newly saved payment accounts will use their token method.