AdMech CL (or normal cruisers for that matter) are indeed the patterns of the IN vessels but with added things (extra dorsal lance, extra repair dice, gifts etc).
However in the AdMech list only the Defiant, Endurance and Endeavour are available as light cruisers, the Dauntless is not. Just as the Dominator, Mars aren't available either.
What I'd advice is depending on what the rest of the fleet has. Are you low on torpedoes add them, do you have enough torpedoes at lances.
Just try them before you make up your mind I think.