Why are some parts in the parts catalog marked with three asterisks (***)?
 

https://cdn.xjjeeps.com/pdf/en-us/19...ts-catalog.pdf

Hundreds of the parts here are marked with ***. I can't seem to find a pattern to it though, or a legend.

Anyone know why? First instance is on page 20 (2-120A), item #20.

*edit* One more question... That's the parts catalog version 81-690-1917. Anyone know if that is the final version produced?

I don't think it means anything in a sense. If you notice at your example there are 2 listings under that for the U bolts. So my guess more then one option for the application. Now what the difference between the 2 U bolt sizes are for is anybodies guess.