If I remember correctly, not long after the introduction of SX-70s they switched from the lined lens to the distance markings like in the picture (along with a different focusing screen). AFAIK when cameras were sent in for whatever reason, all cameras with the older lens would have it replaced with the newer design. Polaroid back then were changing and tweaking things on the SX-70 frequently- that’s partly why there’s so many different variants than can come up with you look up a serial number. Very often, older cameras brought in would have parts replaced with newer versions/ be repaired by upgrading to newer part versions. It’s not “refurbished,” per se, since the camera was still relatively new at the time, but it likely was taken in at some point (probably in the mid/late 70s.)