All signs point to this one being legit, and a very early copy of Dr. Mario.
The first party board has two EPROMS, and the actual number on the board is the number that’s used for retail copies of some first party games. That makes this either a prototype or a pirate cart that was created from another donor cart.
This is possibly the third copy of such an early proto of Dr. Mario, and to my knowledge none have been dumped to date.
Thanks as well to the multiple people who sent me an email about this.