Tire mfg date code/sales

I read an article, a few years ago, about the possibility of a law being passed preventing outdated (something like 6 years) tires from being sold. Does anyone know if this was ever passed? I do know it is recommended to not run tires over 10 years old, and less in extreme climates (like we have in Fl).
The reason I am asking. I went to buy some tires for a small boat trailer, and the "tire store" tried to sell me tires that were already 8 years old. I declined.