I do not think that they can seize your records in this situation. If you had a valid script from a licensed physician, then you have committed no crime. However, they may not be going to be use the info against you, but rather the physician who wrote the scripts. In which case they cannot do anything to you. However, I still can't see the legality of them gaining access to your records without your consent. The government has jumped time over this steroid shit! It is almost like a F'ing witch hunt... You cannot tell me that this is the best way to appropriate our tax dollars... What about Meth, Crack, Smack, or god forbid prescription Narcotics... The biggest problem in my town, is kids selling and using loracets, valium, oxycontin etc... Hell, they will kill someone over oxycontin... Complete bullshit!
Bottom line is that I think that you are fine. Although, I would go see an attorney about it... Good luck and keep us posted!