The Century M1's are USGI parts kits built on commerical *cast* receivers. There may be some out there from such places as Korea built on USGI receivers, but most of those were worn out before they even got here. Depending on the quality of the receiver, you may or may not have a rifle that will function. Some are okay and some are so far out of spec. that they are unsafe to shoot. They have no collector value with the exception of the other parts. Some of the parts used are out of spec. or just worn out. Your best bet is to send it and have it checked out. Headspace, worn parts, receiver, etc. I would send it to Dean's Guns or Orion 7. There are probably other places as well. Fulton Armory does these as well, but they are renowned for being very slow.
Google for the url's or look up at the advertisers on this forum.