Yes, there is a small intake pipe screen that sort of looks like a long bottle cap. It part # 2664. You'll also need to replace the pump gasket if you pull the pump from the reservoir.
One nice thing about piston pumps is that they are bi-rotational so any PTO will work with them. Incidently, your pump is almost surely not original to your hoist as the old underbodies used cast iron gear pumps of 10-18 GPM and the Williams is only 3.7 GPM@1000 RPM. Again, that is the maximum speed so your hoist will operate pretty slowly.
