As my old friend Chuck Evans from the Ibanez Collector's World noted years ago, all of these blonde on blonde MC models seem to have been made in one month, April 1978 (D78). I don;t thikni I have ever seen one as an MC900.
IBANEZ 1978 MC-900 ELECTRIC BASS MUSICIAN SERIES | eBay
IBANEZ 1978 MC-900 ELECTRIC BASS MUSICIAN SERIES | eBay