looks awesome man!!!! you should really seal the metal in paint, primer doesn't seal and still lets moisture in. self-etching primer would also be best if you could. but if you can still paint it i would. not sure if you can get truckbed liner paint there but that would be the best. but ANY paint would be better than no paint when it comes to the primer coating.
it kinda looks like i'm too late though, those metal workers should have known that, bad on them for not telling you.