Yeah, you lucked out.
The part(s) you want are on this drawing:
From BikeBandit Numbers 7-13.
On the Oil Pump schematic available at this page:
Also at BikeBandit
Looks like the combined price shouldn't be more than $28 plus shipping. Also, you might want to factor in some new oil. As far as replacing it goes, it's plug and play. But buy a torque wrench first, and
learn how to use it properly by reading its manual. By that, I mean realize that the GZ torque settings are ft/lbs and some wrenches are in/lbs, so divide/multiply accordingly.