International Jumpseat with combined UAL/CAL
 

I'm planning on heading down to Sao Paulo tomorrow for a week and was wondering what the international jumpseat policy for the combined UAL/CAL.

Can I list for at the gate for the jumpseat as long as there's a seat in the back, or do I need to go to a customer service desk/call a hotline number/or something else to list? Does the same apply for the return trip?

Also, if anyone could give me a load check on the following flights, it would be much appreciated
IAD-SAO Flight 861 Leaving 10:08PM May 8th
SAO-IAD Flight 860 Leaving 10:05PM May 14th

Thanks!