Yes you're right only the ( chopliftu ) set has the full instructions, i'm assuming the unprotected set should be the parent as I would have thought they would sell the protected pcb's first. Are both the parent & the bootleg both bootlegs ? Or is there another revision out there or has MAME's Choplifter sets have a bug or regressed ?
Here's the video I found where the music is playing in the demo about 11 secs in. This version has the full instructions on screen when playing.