Megamania - Prototype or hack cart?

I pulled out my 2600 stuff today from my childhood days and noticed this cart. I opened it up and took a couple photos.

My best buddy's dad was an electronics guy and he would bring home games on eeproms and things, so I just figured this was some hack cart from way back. Any chance it might be more than a hack?

The number on the back of the cart is:AG-910-02A

When I turn the game on, it looks complete as I remember the game.

Thanks,

James