you have 3 main ways of mounting a scope red dot.
use the actual Scope mount system that is embedded onto your reciever of the ak. This is the "box" looking metal piece on the left hand side. This is the most secure and were a scope was originally designed to go. I have my scope mounted from this location. the example given is a tri-rail. The one i have is specificly meant for a scope, as my mount at rings and not rails.
http://www.copesdist.com/images/AKSideRaliMnt.jpg
http://www.copesdist.com/images/mtK-83.jpg
If you get a front handguard set with picatiny rails on the top and bottom. Then you can mount small red dot. on it. Iv seen a few have it like this.
http://www.copesdist.com/images/mnt-hg478sa-a.jpg
http://www.copesdist.com/images/FABAKUpperHandguard.jpg
The WORST location, is a dusk cover with rails. pretty simply as to why, the dust cover can tend to slightly wobble and it is really not secured down tight, the only thing holding it is the back end of the spring button. that right there would turn me off from the rail cover.
http://www.copesdist.com/images/mnt970trm.jpg
for all your ak needs.....
http://www.copesdist.com/ak47.htm
best site ever.
and if you a bigger guy, like i am. Get the SAW pistol grip for $20 tapco makes. Counts as a US part and its much easier on the grip for larger hands.
http://www.copesdist.com/images/STK060223_md.jpg
hope this info helps
Drakin