The rack looks older than my '39 Columbia..
I second the above;The Chain Ring says Murray..
Can you get a better shot of the Head-Badge or Rear Dropouts?
The paint looks like a Housepaint Redo, so the Serial might be buried but preserved with any luck..
I'd put it late 40's early 50's maybe? but thats a guess from someone less experienced.
Whats there looks Original.
Stay tuned, you'll get an answer soon.
FZ