Yes, you are posting just fine! Here's a link to ball joints for a 67 C3500 at Rock Auto.
https://www.rockauto.com/en/catalog/...ll+joint,10070
I'd go with Moog or ACDelco, in that order.
For Tie Rod ends, sleeves, etc - close the suspension section and open the steering section and you'll see several options.
If the ball joints are tight, they probably don't "need" to be replaced, but it's still not a bad idea. Can you tell if they have been replaced before? (probably have). If they are tight, I'd decide based on crusty factor... Can't hurt to replace them though - same for steering components. Is your steering sloppy?
Btw, the GMC 1 ton is a 3500, 3100 is an older era term for a 1/2 ton.