u/Bee_The_Miata

This is my first time attempting to completely rebuild a motor and i'm using a 302 as a learning experience. I'm tearing down the motor right now, and I just got the lifters out. After wiping them all down, I noticed that 5 of the lifters (bottom left of photo) have rings around them on the middle dark section, and the other 11 do not. Is this normal, and could I just tear the lifters down and rebuild them or do I need to get a new set? I don't have any big horsepower goals with this motor, just want to rebuild it and it actually run, so no need for any upgrades unless what i'm working with just absolutely will not work.