Requirement for pressurized components

[YankeeClipper]

Increasingly, it seems, the planes that appear on market are P's (which perhaps stands to reason on a number of fronts) and there is much to read of course on the pros and cons thereof. But if the pressurization systems fail, and your mission doesn't require them, can it pass an annual without? Can it pass with some of the components actually removed ?(Naturally one can't remove something that would also affect some other system).