Snyder built and Westfield built Moto-Balloon frames do not look much different but yours appears to be a Snyder built frame. The upper rear fender bridge has more of an arch than the contemporary Westfield frame and I believe I can see the vestigial lugs on the crank hanger that locate the seat and down tubes. Those are a Snyder hallmark. The serial number is also more in the pattern (and content) of an early Snyder number than a Westfield number.