Yes. To tell if they can be posted or not is to see what type of file it is. If it's a .swf file then you can post it. I've made a few games with Stencyl and they're all .swf files, so no need to worry about that.
On that thread with the free programs Game Maker games can't be posted here since they are not .swf files.
You can make games with the program Game Maker but can't post those on AG since they are not .swf files. However, you can make games with any of the others and post them here.