Doesn't look like it. The chainguard has a row of dimples across the bottom. Repainted. Straight fork version. Missing some of the trim parts. google for "the ultimate spaceliner guide" that documents all the Spaceliners. Manufactured by Murray who also sold the same bike with other names including their own. The serial number will tell if it was sold at Sears or not.
Sears sold products often have a 3 digit supplier code. The bike suppliers were in the 502~505 range. A Spaceliner serial should start with 502 (murray).
No doubt that it is the same frame as a Spaceliner. It is either a Sears Spaceliner or one of the other reseller names that Murray marketed these to. Very unique and cool frames that are so versatile to build.
Here is a Ranger I had a few years ago. It has the same dimples on the bottom edge of the chain guard as the op's photo. it was one of a his & hers pair. The previous original owner told me his dad got them new as presents for him and his sister at a store somewhere in Chicago but couldn't remember the store name. We figured he was about 12 years old when they got the bikes.
The serials were
MOW 51X15 397509
MOW 74X15 520472
Sears Spaceliners would have serial starting with 502, then the Sears model/catalog number (46xxx) then the unique sequence number.
Murray manufactured the same frame for many brands but the bolt on parts, colors and decals would often vary such as painted rims vs chrome, painted fenders vs chrome, different shapes for the chain guards, tanks and racks, different tank extras (lights, horns), etc.
The serial number on the op's bike frame will confirm or eliminate the "Spaceliner" model name.