Very unusual CBS DK Jr. Cartridge!

[Robotube]

Recently acquired this very unusual CBS ColecoVision Cart of Donkey Kong Jr.

 

I've played it a bit and cannot find, at first glance, any strange characteristics in the gameplay that would lead me to believe this is a prototype. But the cart itself is very odd. It has no label and does not appear to have ever had a standard label (no glue or paper residue at all) and has just one circular CBS Colecovision metallic foil label that is definitely not home made, and appears to be as old as the cart itself, leading me to believe it was placed there at the time of manufacture. 

 

This may be very mundane and experts probably have seen these before, but can someone shed any light onto this for me?

 

Thank you!

[mumbai]

Yes, actually, this very cartridge I have seen exchange hands on eBay over the years on at least three occasions (including the auction from which I imagine you acquired it).

 

I could be mistaken, but that decal is lifted from a replacement set for Expansion Module #2 (the steering wheel).

[Robotube]

AH ha! Mystery absolutely solved. Thank you! It was a fairly cheap lot so I don't mind. I just have 4 doubles now if anyone is interested.