I have a CB600F "Hornet" model PC41 from 2007 which has an upside-down fork that is not adjustable.
The same model code PC41 was used on the "CBR", sharing engine, frame and most other components, adding a fairing - and the same fork, but with adjustable rebound damping and preload.
Now by the parts catalogue it seems that my fork can be upgraded to adjustable just by adding the "Bolt comp, FR Fork" part - see here.
Can someone confirm this?

 

As far as I understand, it was the CBR600RR (PC40) that had the adjustable forks whilst the CBR600F (PC41) reused the Hornet forks.

The RR internals look significantly different and I doubt that it would be as easy as just changing the one component - more like a front end swap.

 

The PC40 parts may be totally different, here we are talking only about PC41 variants.
Some PC41 models from 2007 on and (AFAIK) all after 2009 had adjustable forks, in both Hornet and CBR600F models.
This parts catalogue page shows both variants in one picture - and obviously both use the same damper (#9).

BUT - using a USB endoscope camera to look down inside the damper where the rod ends - I found a drop of glue blocking the opening.
So it seems Honda anticipated the idea to upgrade the part - and decided to hinder such efforts.

 

Then would the easiest option be to replace your forks with those from a CBR600F?

 

Yeah, thanks for the lecture on plausible reasoning.