Rampo, it's a truck by most all definitions and jurisdictions. But, regardless which definition you are pursuing, the only one that holds any water here is the definition of the condo association. Not that it matters, but what does your license plate/registration say: Commercial, Truck, Passenger?
Regardless, private property owners can give all "red vehicles" a citation if they so wish, and as long as people are properly warned.
Sounds like you knew this might happen, were concerned, pressed your luck, and it did. Seems to me that a call prior to the association could have cleared it up and maybe gotten you a "pass" or would have given you an indication if there were any way around this.
Oh, and one last thing, the condo association no doubt has this "law" because it wants to make sure that work trucks from crews working in the condo, and work and service vehicles owned by members within the condo are not parked there overnight. Sure, the enforcement and letter of the law seems a little heavy handed, but it seems you knew about it beforehand.
Sorry if my tone seems harsh. I am just a stickler for following rules and personal responsibility.
Pay the fine, lodge a complaint, move on with your life.
TJR