Yeah, it just gets ignored in those cases, I did that with the Slaves to Yisun: Chapter 1, Reach HFS Through Violence (Kill Six Billion Demons) mod I've got baking, added multiple small/internal limbs which use a material with better weapon properties and added them in the template before I learned I can just use the tissue:blade, *define it*, tissue_layer:by_category stuff, though after checking demon masks get a b_detail_plan_default.txt entry under my strong_materials and strong_tissues plans which are also used by several other critters that don't end up with a mask.
Oh yeah! You can assign materials and even swap them out with c_variation_default.txt lines, have it go through and look for body_detail_plan master and standard_materials target then swap it for strong_materials and it just fucking works, boom.
I used these because I wanted certain features of the bone templates with the steel properties so it was easier like this instead of just having it use steel directly, but yeah, tossed these in a creature variation like the animal person ones and pow, it spits out a totally swapped over material critter:
[CV_NEW_TAG:USE_TISSUE_TEMPLATE:BONE:STEEL_BONE_TEMPLATE]
[CV_NEW_TAG:USE_TISSUE_TEMPLATE:SKULL:STEEL_SKULL_TEMPLATE]
[CV_CONVERT_TAG]
[CVCT_MASTER:BODY_DETAIL_PLAN]
[CVCT_TARGET:STANDARD_TISSUES]
[CVCT_REPLACEMENT:STRONG_TISSUES]
[CV_NEW_TAG:USE_MATERIAL_TEMPLATE:BONE:STEEL_TEMPLATE]
[CV_NEW_TAG:USE_MATERIAL_TEMPLATE:SKULL:STEEL_TEMPLATE]
[CV_NEW_TAG:BODYGLOSS:LEATHER]
[CV_NEW_TAG:BODYGLOSS:SKIN]
[CV_CONVERT_TAG]
[CVCT_MASTER:BODY_DETAIL_PLAN]
[CVCT_TARGET:STANDARD_MATERIALS]
[CVCT_REPLACEMENT:STRONG_MATERIALS]