Great job DBLOCK. You're machine looks like it's in realy good condition. If you haven't already, finish lubing all the specified points in the manual. Some are under the machine. That should help improve smoothness a bit more. This link is to the manual: http://www.ismacs.net/singer_sewing_...ine-manual.pdf
This website if chock full of helpful info for older machines. You can even look up the serial number to date it.
You've got something that'll last another 50 years with care.