HP 1141A probe attenuator HF response adjustment questions

[hasc]

I have several 1141A probes and attenuators bought from different sources. The manual says the CMRR and HF response of an attenuator needs to be adjusted with the specific probe it will be used with. Without having made any adjustments yet, just trying different combinations of attenuators and probes, the performance generally looks reasonably good (roughly 1000:1 CMRR, step response flatness well under 10%) but there is a fair amount of variation across probe/attenuator combos which I think indicates that probe-specific adjustment could help.

However I am a little worried about attempting the HF response part of the adjustment because the two surface-mount trimmer caps have been filled/locked with what appears to be RTV silicone. I don't see the silicone mentioned in the manual but it is on all the attenuators I have and is also visible in the photo in this thread:
https://www.eevblog.com/forum/reviews/agilent-(hp)-1141a-differential-probe-and-power-module-1142a/

Does anyone have experience adjusting these attenuators? Is the silicone just there to prevent casual twiddling or could there be some other reason, like sealing against contamination? (The manual does say not to do the adjustment as part of normal maintenance because the attenuators are delicate...) Should I risk picking out the silicone and messing with the trimmers? Or just do the LF CMRR part of the adjustment only, leave the HF alone, and swap around attenuators/probes to find the best combinations as-is?