OK, you have found a barn fresh Cushman. It has the classic Cushman body, but you don't know how to tell which model it is. The differences seem subtle at first, but they are very different scooters. The 50-series model years were 1946 to 1948. The 60-series were from 1949 to 1956. Look for these differences:
Early 50-series had pencil springs in front. Barrel springs were used from mid-1947 until 1956, so if it has pencil springs, it's a 1946 or early 1947.
Look at the kick stand. The 50 series used a flat, straight kickstand with a steel pad on the end. The 60-series had a round kickstand with a curve near the end, but without the pad.
The 50-series had a smaller tail light with a metal guard around it. The 60-seris had a larger one without the guard.
The body of the 50-series goes straight down on the sides, but the 60-series flares out and is several inches wider at the bottom.
The 50-series has a two-piece block Husky engine. They call it that because the cast iron oil sump on the bottom is attached by bolts. The 60-series used several different versions of one piece block Huskys. They had a flat sheetmetal oil pan bolted to the bottom. It was more prone to oil leaks, but more powerful.
Eight-inch or six-inch wheels are found on 50-series and 7.75 inch wheels are on the 60-series. The six-inch wheel has a fat tire.
The 50-series Cushmans have a Permalite generator mounted on the right side of the engine. The 60-series has lighting coils in the magneto.
On the rear of the frame, a 60-series will have a curved brace between the tops of the rear springs. There is no brace on the 50-series. That part was probably put there to reduce flexing and prevent cracks in the frame.
The 50 series fuel tank is mounted on the back of the engine. The 60-series fuel tank is in the same location, but it is mounted on the body.
Both series had some models with a transmission and some without. The quick way to tell the difference is to look for a clutch pedal. The single speed scooters were the model 52 and the model 62. Some 60-series Cushmans had Varimatic transmissions and some had the two-speed.
Howard