I have installed them cold, but I saw this recently and it made me wonder.
http://www.akparts.com/akinfo7.html How to Install AK-47 Receiver Rivets The Easy Way Grab the rivet with a nice pair of insulated pliars, a leather glove is a nice thing to have here too. Heat the rivet shank (not the head) until it's RED. Use your pliars to install it in the hole, place your tool you made on the top of the button head and slowly press with a shop press OR gently tap the tool with a hammer. It won't take much pressure with the rivet red hot. It'll squish in the hole easily, just make sure you tap the rivet head all the way down until it touches the receiver. Let it cool, and you're ready for your next rivet. Remember, the object is to distort the shank of the rivet at the bottom. We have to make it bigger at the bottom so it won't come out of the hole.
The method described above (with heating the rivets) is an alternative to "screw build". You don't press the bbl out, but as with screw build, you drill the old rivets out, slide trunions in to receiver, and follow instructions above. It should work, but the heated rivet may come out to "soft".
It is not necessary to heat the small rivets we use on AK builds. They do not form any easier or better heated. They also do not draw up anymore when cool considering you are working with sheet metal and not thick steel stock. I tried heating them when I first started building and ended up just grabbing them out of the bag. Too much work with no gain. If you are using large steel rivets (1/2" or bigger)it is required to heat them for several reasons. They are easier to form and draw up when they cool.