The parts are all one disc. Sorry it took so long to answer that question. :P
Anyways, I found these while digging through my hard drives for something. I made these images back in July of last year (about one or two months before Sonic CD got put on Abandonia). They're the covers and disc label for the custom "Japanese Music" ISO that I made. It's not much, but it gets the job done:
http://img14.imageshack.us/img14/2838/soniccdpcjpfrontcover.png
http://img819.imageshack.us/img819/5438/soniccdpcjpdisclabel.png
http://img52.imageshack.us/img52/6171/soniccdpcjpbackcover.png