Zombieman Variant Differences?

I noticed that plasma rifle zombies come in two different variants: some are wearing a dark green vest, and others a heavier-looking set of tan combat armor. This strikes me as weird given that everything else incl. faces are the same on these models. Cosmetic variation in demons is generally limited to fodder-zombies, and those tend to differ level-by-level, remaining identical to one another therein. Only soldier zombies seem to have differing models than one another in the same level.

Are there any observable mechanical differences between these guys (e.g. durability, able to use their jump-jets, etc.) that have been already noticed?

Probably just the lighting.  Otherwise I need a screenshot.

Alright. Having looked at some slomo footage I think I was mistaken; soldier armor comes off in one piece when they get shot, revealing their uniform beneath.

With armor.

Before getting shot, armor intact.

Right after they get shotgunned, the frontal plate on their vest can be seen sailing off to the right.

Glory kill, closer detail on the uniform.

Shot from the Phobos trailer of an "undamaged" zombieman; hasn't taken any wounds yet but still lacks their vest.

Ditto, facing the player a moment later.

The presence of unarmored zombieman that hadn't lost it due to player damage points at either this feature being cut pre-release, or demon infighting (which otherwise does not appear to inflict damage of any kind) being capable of damaging zombiemen.