is it a hg or a oc3?

[duckft]

Hello :
     I am new to the discussion board and already I have a question. I recently bought an oliver crawler with no name tags on it. I was told it was an hg which belonged to the mans' father who bought it new. The engine is original to it, with an engine serial # of 2447550 and IXB3 on it. It has a wico mag# 1113b and a tillotson carb, model # YC10A. There are no tags or numbers on the frame or bellhousing. Can anyone tell me the year and model(HG or OC3) from this information?
    Thanks-Kel