On your cam, it is highly recommended that the lifter be matched to the cam lobe. Since your cam is fairly new, if you didn't put the lifters back in the same holes they came out of, you will be better off in the long run to put in a new set of lifters. The cam lobes have a slight taper to them, which forces the lifters to rotate and not matching the lifters to the lobes can cause the cam to wear faster.
The break-in period on the cam is to allow the lifters to wear to match the cam lobe. Once done, it doesn't need to be done again as long as the lifters remain in the same position.
