As the tour info from the RS office says, you will need a passport sized photo for the Metro pass so make sure you either take an extra one with you or photocopy your picture page in your passport. I somehow overlooked this instruction (as did others on my Best of Paris tour) but the hotel was quite happy to make a photocopy of my passport photo. Don't cut it down until you get there as your guide will have scissors and a template to use to make it the right size to stick on the Pass. It is a bit smaller than our passport photos so most of us wound up with some hair being cut off. (The picture, not in person!)
In fact, I would just go copy that photo page right now and put it in your pile of stuff. You DO have a spare bedroom dedicated to this venture, don't you? lol!!
Being provided both the Metro pass and the museum pass was wonderful! It made me realize that if I go back to Paris for a week, I will try to time it so I can take advantage of reloading the pass for my use.