Should I go on the warpath to purchase some of these for my Wild, Wild West Signature Set?

While browsing a few of my favorite coin web sites, I've come across coins (comparable I guess to our commemorative coins) put out by the Shawnee and Poarch Creek Indians. As you all can imagine, these coins arouse my curiousity, and the Shawnee coins especially would fit in wonderfully with my Wild, Wild West signature set.

Now, since my coin budget is limited, I have questions. Can these coins be classed with modern US commemoratives (for example the Bison commemorative, the Lewis & Clark commemoratives etc.)??

Will NGC grade these coins?

Any input from any of you would be much appreciated.