Not all scales. Using fish bones for bolts is dumb enough as is, adding fish scale armor would get eye roll worthy pretty fast.
I don't know, fish bones regularly seemed to on the verge of doing in HRM The Queen Mother (maysherestinpeace), so a carefully aimed fishbone bolt could well be quite fatal to any gobbo whose comrades were unaware of the Heimlich Manoeuvre.
But, as for the OPs original idea... Dragon scales being used in Scale Mail, came to mind[1]. Which means something other than merely making these items behave 'shell-like'. Not really experienced with that level of Modding, but what with the noun and adjective aliasing that I think can go on, could this be partnered with "dragon shell" (a.k.a. "dragon scale") being used in a custom reaction where other types of shell cannot? And/or allow normal "shell-mail" to be possible but substantially less advantageous through the intrinsic material properties.
[1] Which is traditionally a formidable protection, so should probably require effort or to make. Whether that's something primarily represented by needing a number of scales equal to multiple (normal-sized) dragons, or merely to be represented by the very first intstruction in the manual of "First, kill your dragon", would be a point of discussion.