I've never noticed a problem with OCO as long as I used a Bashed Patch and proper tags. This question is actually brought up in the comments sections for both mods. The author of one, michaelt919, admits that he doesn't know much about Wrye Bash and so he prefers to make his own manual patches instead. There is a brief debate in the comments section for the second mod about whether that patch is needed also. A poster says Bash fixes the Horse Armor issue, while the mod author disagrees. And that's how it's left.
My guess is that these patches are probably not necessary if one properly uses a Bashed Patch. Like I say, I always Bash Patch OCO and I've never noticed a problem in my games. *shrugs*