Rare is a relative term. Anything extremely rare will be unlikely to be found at a junkyard (like rear seats, from abroad).
'85 Si spoilers, was well as '86-'87 Si spoilers, weren't rare when new. OTOH, finding one in really good shape these days would be a great find.
(I have 4 '85 Si spoilers and 2 rear red reflectorized center panels, but they are on my cars.)
Keith, who has found genuine Honda louvers, a red reflective CRX center piece, a Dew Blue '85 Si center console/equalizer holder, and many other good CRX items in junkyards...
Keith A. Edwards
Suffolk, VA
1.75 1st gen. CRXs
former ECHC H5 Champion