Here's one place that might help you out. Good luck.
Is there somewhere online other than Ebay to find used parts?
Numrich (Gun Parts Corp) and Brownells both carry parts, Brownells new parts only. For older guns, try Dixie Gun Works.
Dave Clements Custom Guns makes new parts for older Ruger three-screw guns.
And, larger gun shows usually have dealers selling parts.
Thanks for the info. I'll give them a look.