It's a knock off from 1984 from the Taiwan "Cassette Man" line of bootlegs.
Here is from my personal collection to compare
They also came in Microman-like cases with the paperwork and all but didn't have the Takara stamp on the back of the robot mode "butt" or in the paper work. ALso no TAKARA on the chest sticker of "Rumble" No MC (Micro Cassette) proper number either (60?!) on the paper work.
Hope that helps!