Yonezawa were in recycling mood when Mr Jupiter was designed. The head is Mr Robot's (Kit #24), as are the arms; the body, with a few minor alterations, legs and feet are Mr Mercury's (Kit #120). They've even used the inset litho circuit design from the latter. As an original touch the robot has been given a distinctive new paint job, predominantly lithographed. The result is a hybrid robot that is extremely rare. The box art is simple but very striking.

Clearly if Yonezawa made this robot, then they had a hand in Marx's Mr Mercury as well

The robot is very rare and very highly priced.  This is definitely a case of the whole exceeding the sum of the parts.