Mike,
That is true, our information was that the unit should not be drilled or cut open, otherwise it is safe, who would want to cut one open anyhow, not much you can do with it if it does pack up!
Another component for CVR vehicles, with a Beryllium warning on the packaging, was a nodescript metal washer used on one of the wiper arm linkages, for sight or periscope, think it was a sort of shim or wavy washer, but put the fear of God up me when you think how easy it would be to cut yourself on it.
Another hazard warning I recollect, was Viton, if it had been in a situation where it was burnt or charred, then handling it could burn your flesh away. Some of the fluid flywheel seals at that time were made with this material and were quite often burnt where they had leaked and overheated. Hope this has not scared too many people, but engineering has more hazards nowadays than you may think!
Richard