I have been wanting one of these since I first saw them here. My mom had a similar machine, but I think it was a 400 series, not a Rockateer. I can not find a serial number but she is a 503A. And she is in perfect condition except for one minor thing. The top hinge on the front door is broken. But it closes and stays closed so I am not too worried about it. There are a couple of very tiny dings in the paint and the cabinet has some rub marks, but otherwise she is perfect. The box of attachments look like they have never been used. Even the oil is unopened. And the instruction book is like it was never opened. The cams are still shiny, like they have never been touched. I was told she was serviced on a regular basis, although I am not sure why since she was hardly used.
Today I cleaned and oiled her since she has been sitting for a long time. No fuzz or thread to be found. Then I tried sewing on her and wow, just wow, she sewed like a dream. Even the tension was great.
My husband found her on Craigslist and the lady had her listed as a 301. She was listed way back on Jan 1st. I called and she was still for sale, so I was excited. This was a week ago and the lady could not show her to me till this past Monday. Made for a long weekend. I was afraid someone would buy it out from under me. But I was lucky and now she is sitting in my living room. I just love her pretty cabinet with the sexy curvy legs.