If the pyro stained negs are intended for silver printing then yes, any
color densitometer can read these thru the blue channel, however if the pyro
negs are intended to be used for alternative processes (which they often
are) like pt/pd that use a UV light source then you need a densitometer that
can read thru a UV channel. The models that can do this are few and usually
quite expensive..i think the densitometers that have a UV channel are/were
used in the production of silicon chip wafers that originally start out as a
film that is exposed to UV light I believe (but I could be wrong about
that)...

I know x-rite has at least one model that has a UV channel capability...

Ebay. Won't any of the colour models work? If so mine cost less then $100
but it's also 30 years old.

Nick