I made those catwalks from scratch using the same textures Valve used on Granary.
I can't believe you've taken so much time to prove yourself that they're "stolen" from Granary. I can point out many details from someone else's TF2 map which are "stolen" if I want to but I'm not going to bother. I'm just using the same style they have in TF2 just because this is a TF2 map, right? It's not called stealing, it's called keeping the art direction and look of the mod you're mapping for and with limited assets, there's nothing much to improvise with catwalks.