In the photos they appear to be in order of the earliest at the top and the latest at the bottom. I base this on the rear section of the manifolds where on the earliest one, the cadmium-plated steel inserts for the windshield wiper vacuum line and the never-released vacuum line for a vacuum-assisted clutch (the plugged hole) are in place just like a '32 manifold. The center manifold has only a threaded hole for the windshield wiper vacuum line, but the bosses in the casting are the same as the earlier manifold. The bottom manifold has a relocated boss for the windshield wiper vacuum line (and the boss for the vacuum clutch line remains).
Unlike all '32 firewalls, '33 firewalls have no obvious provision for mounting the vacuum canister associated with the never-released vacuum-assisted clutch (for which Ford sought a patent and received it several years later, long after any plans for one had been permanently shelved). The lack of attachment provision on the firewall and the changes in the three manifolds shown seem to confirm the eventual demise of the idea.