COO's

When buying loose figures I've never really paid much attention to the year or COO, but I've noticed when selling in constantly asked for the information. Are some COO's much rarer or valuable?

Is there anywhere I can research the various combinations for figures?

Any advice welcome. Thanks a lot everyone

These links should help,

https://www.imperialgunneryforum.com/Vintage-Star-Wars-COO-Guide-h14.htm

http://www.highasakoit.co.uk/starwars/starwars.php

Some COO's or lack of do make the the figure more valuable and often the figure will have a slightly different mould or paint application as well, such as foreign variants like Lili Ledy, PBP or the Tri Logo Boba Fett with a single or double scarred out COO. I'm not really a variant collector so outside of foreign variants I'm not sure how much a Hong Kong, China, Taiwan COO, or no COO, of a certain figure effects the price or desirability, but I'm sure somebody will be able to help a bit more.