To my knowledge, no one ever made laser sights for any of the Colt handguns. I don't know if lasers are "a waste of money", I think it's a question of personal taste, but I happen to like them and like to have them on handguns I carry for self defense. With the newly manufactured Colt's Detective Special, there may be laser grips made for it, but I doubt they'd fit without modification. If you're willing to sacrifice the money, you could probably find a gunsmith that could modify an existing laser sight or laser grips to your Colt Agent, but it's not likely to be either easy or cheap, and it might even involve permanent modification to your Colt Agent (i.e. drilling and tapping holes in the frame.

Regards,

Dave