Did you look on the crane for a model number? It might not have one, sounds like a Chiefs Special, in 1957 they started stamping the model number on the Chiefs Special and they were known as a model 36 from then on. If it's a Chiefs Special, it is over 50 years old. We would at least need the serial number on the butt, you can x out the last few numbers if you want.
Does it look like this?