For "real" turned rivets ( and hex bolts ) go here:
http://www.scalehardware.com/
Many of those he used are "just" photoetched though.
There's a set of these from Scalemotorsport ( can be found at many shops ).
For really small ones search for MCG ( Model Car Garage ). I have their set "MCG-609" and they are the smallest i have ever seen :-)