The last # looks like it could be 6,8 maybe?? Someone said the chainring was CWC and then someone else said the frame was prob AMF after CWC was bought out??
I couldnt get any pics but I looked thru a magnifing glass and the last could be a C but no w that I can see, must be a real weak stamp I guess.
I will just call it a 50's somthing