From the picture you have an olde NACRA. I would not try to get the parts to fix it but would use this site to find a used one. The fastest and easiest way to go. When you get one, just remove the end stop, slide off the old put on the new, replace the end stop and go sailing.
nacra switched from schaefer? parts to harken parts about 1980?
that must be the older stuff
i think older harken cars come with loose delrin balls and the later cars come with captive delrin balls, important to have the right number and not too worn
it looks like the old one could be salvaged but you'd probably have to work it out yourself...
the 80's replacement looked like this but was blue
Going down memory lane, how fun . . .
The difference in the red and blue NCB travelers (as well as furlers) by Harken was price, payload, and balls. Blue was loaded with Delrin, and red was loaded with Torlon. The balls (bearings) are the same size and it was common that folks would change out the Delrin for the Torlon for a quick and cheap upgrade.
Gray, back to your original question in this thread. Looking at that photo I think there is an easy fix using what you have. The eyestrap that is attached to the blocks would attach to each traveler car via a threaded bolt (one is missing, the other is still there). What has likely happened is that galvanic corrosion has compromised the alloy and it has pulled out. The easy fix would to get a couple of SS bolts a size larger and tap the traveler cars. The spacers (new and larger to fit over the larger bolt) need to remain as they serve as the reef point for your traveler sheet. Should be an easy fix to put it back to its original design.