You are correct Winnie. The bolt head is the only difference. You're on the right track....keep us posted on the build.
Just a side note. If the action you get is a standard cartridge, you may need to open up the magazine lips some to feed a mag cartridge. Its no biggie at all, just a little heads up.
Hope this helps.
Feel free to ask more if need be or PM if ya have any questions.
Scooter