Contra 4 most likely is Final Mission hack, and Contra 5 is GI Joe 2, as I found on youtube.
Does anyone ever seen this parts on real carts?
Yes, I have a copy of Contra 5. Hold on, I'll take a picture of it.
Edit: Here ya go.
(http://gyazo.com/31c83b81da26cc542e00dd5d6473aadd.png)
I like the star molded into the cartridge. However, the game itself disappoints me. I absolutely adore Taxan's original G.I. Joe game, but The Atlantis Factor seems to be a downgrade in every single category. Very disappointing sequel, but oh well.
In this page (http://web.archive.org/web/20110102154101/http://contraseries.weebly.com/pirate-cart-scans.html) has pictures of these and other Contra carts.
oh, great, thank you!
however, still nothing about Contra 4