Cell Rot or not?

Wise move, it could be off gassing but just not enough to eat the metal, yet.

I honed a beautiful French grind Daniel Peres that had some funky celluloid scales that had dull spots with lots of cross checking on them.

I honed that razor regularly a couple times a year for several years and advised him to re-scale it, before the gas ate the steel. It never did, but eventually I did re-scale it in Reindeer that his brother collected as shed and sold as dog chews. It came out beautiful. The off gassing never did affect the steel.

The problem with celluloid is the makers were attempting to make unique designs and colors back in the early days of plastics and use an un-know concoction of chemicals.

Some celluloids off gassed aggressively and ate steel, some just looked funky. Removing them was a wise choice. Make a template, before trashing them.

Make sure to get rid of the wedge, if it is celluloid they are often the cause of the start of off gassing.

Those were almost certainly one of the several formulations of hard rubber scales. Whatever was on them probably wasn't any danger, but hard rubber scales are not particularly repairable or precious. No reason to not dump them, and I'm someone that will move mountains to fix old horn scales.