Gas key was staked so good that I stripped out the hex screws trying to get them out.
Any suggestions on how to get them out now.
Do you have a grinder? Grind them off until you are below the bolt head.
Easy-Outs aka Screw Extractors
http://www.jamestowndistributors.com/1/1/334-drill-bits-screw-extractors.html
If you have a dremel, using a small red cut off wheel. Cut a slot through the hex head. Use a flat head screw driver to remove the hex screw.
Not sure what type of hex you are using but I think that you’ll find using the Magna-Tip sets from Brownells work better. You may also want to consider that some manufacturers have been known to use Rocksett or other high temp thread locker as well. I would try and heat the screws and see what happens.