[morzh]

Ah those....I thought you referred to those in your photos. Yes molded mica-likes may have to be cut. Not sure how convenient it is and whether it is easy to do, this is why they are molded - the outside is some sort of resin or epoxy and I am not sure it will easily lend itself to cutting. I think it will crack and go in pieces.

I would just replace it with a suitable cap. As much as I like to get as authentic as possible, I easily compromise when I see that the effort is disproportionate.