There are perks to getting an extra starter box. You get quite a few extra models that can be used, extra cards, tokens, dice, extra map, extra rule books, . . . . what’s not to love?
The core box only has four “Uniques,” Sole Survivor, Aviator, Goddard, and Dogmeat. Dogmeat even has a “Dog” card available through another set to make it usable as a non-unique model. In other words, if you need the extra power armor model, there are worse ways to do it. 
Also, not sure if this helps or not. If you know someone with a 3D printer, this might work for you:
A fellow gamer who I met recently was kind enough to print one out for me and it looks fantastic.
You can see the picture I took of the one I received through this link: