I actually had a 317 with the Onan engine at one point in my herd...It came as a sad, mistreated tractor with lots of pavement sealer on it and I cleaned it up a bit...
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Here is a serial number to model year map from the PC1698:
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Your serial number makes it a 1980 model.
Below is a PDF document that lists all the attachments and the models they fit for the vintage Deere garden tractors...