Ahhhhh...if you had told us up front it is a MiniMax it would have saved a bunch of guesstimating.
I built a MiniMax twenty years ago (alas..it has since been removed from the land of the living....) and it is one of the most beloved little wood airplanes ever drawn to plans (or kitted). This is an aircraft that definitely falls within the 51% rule regardless of whether it was built from plans or a TEAM kit. It is very unlikely it was professionally built because the profit margin would have been too thin to make it worthwhile.
My MiniMax:
There is only one version of the MiniMax that is Part 103 compliant, and I bet yours isn't. The Max 103 is a stripped down version with a single-cylinder 277 Rotax. Most Maxes were built with a twin 377 Rotax.
All you gotta do is get in touch with a DAR, tell him what you have, and let him send you a doc package to get the process started. The DAR will conduct one inspection and make sure all paperwork is in proper order.
All this info and links to most of the docs is available on the EAA site:
http://members.eaa.org/home/homebuil.../register.html
Here is technical support:
http://www.teammini-max.com/
Enjoy your great little airplane!