If you make your mod and want to take models from Contra then you are allowed to take those models which were rejected. The latest official release for now is Contra 007. You are not allowed to take anything from it, but you are allowed to take old stuff from older versions which is not used in latest release anymore. Before you take an old model, make sure that it is not used in Remix because some models were taken from there. After you take the model, you need to add a short string to your mod description (as well as to credits page in the game) which elaborates that some models were taken from Contra.