Thanks mac! They do mention not getting threads of cloth from patches getting stuck in the gas port. No idea if I did and not sure how I can check without removing the piston. So the answer to my question is don't worry about cleaning the piston but also don't get cloth threads caught in the gas port.
Yup and clean with soap and water and apply rust prohibitive after , we really have complicated so much in the past 50 yrs.
Theres also good info in that manual on how to shoot your carbine better.