the sunroof mechanism is in the FSM for the 85 crx si.
i bought my first FSM in 1985 after i picked up my 1985 crx si. the FSM was actually one for the civic which it shares its running gear and a thinner supplement for items only on the Si such as the fuel injection system and the sunroof, etc..
and if looking at factory sticker pricing sheets, it is listed as standard equipment.
Of course, the sunroof mechanism is in the FSM, just as it is in any vehicle that has one available as a factory option. But does it document the fact that the vehicle is not available w/o one?
I don't think window stickers are considered as official documentation.
Again, I'm playing devils advocate, I know from personal knowledge that the Si was only available with a sunroof, but personal knowledge is not supposed to mean anything its a matter of what can be documented.