Yea, it's Murray.
Could be flite series, possibly a skymaster. Hard to tell without the tank or bezel. I'd say mid 60's, 63-66. Serial number will let you know for sure. Cool frame.
Edit: I need to pay attention. Pic of number, seems odd. Is there a number on one of the dropouts?
if it has 2 serial numbers, that's usually an indication that the bike sold thru a third-party retailer, meaning that although it is Murray-built, it probably didn't wear a Murray badge. Sears sold a lot of Murrays over the years, many under the JC Higgins label.