We have 50 or so 90 min. doors manufactured by Fenestra who apparently
went out of business around 1994.  We know they are fire rated because
we have inspection documentation from 1981 indicating they are.  The
problem is we can't find any label, plaque, embossing, etc. on the
jamb even after scraping 20 plus years of paint completely.  We can
find it on the door but the local inspector isn't accepting that alone
for the jamb.

Does anyone know a "secret" location or code that might prove these
jambs are fire rated or some other way of "authenticating" the jambs
that will satisfy a VERY picky inspector?

TIA