I am looking for parts for my Pettibone model 204-A serial number 1671
Welcome! any particular parts you're looking for?
All the steering components
I'm gonna guess the cylinders are specific to Pettibone, but could be rebuilt by anybody with seals measured to fit. The valves are probably third party, so you could look on the unit itself for ID, or contact Pettibone for a parts manual, they're very much still in business and you could buy a new one just like yours.
landmark machinery in Portland -- ask for earl