[Phlogiston]

For special radios I have made molds for recasting those caps, like with the resistors. There are some pictures on my blog of the ones I made for both of the Strats I did recently. They were .01 as I remember. This is a large value for a mica cap and a giveaway that they are in fact paper.

I would have to look at the schematic, but I would rather cut one leg than leave them in circuit and that is assuming that they are part of an unused circuit. (as you say)

One of our local AM stations has quite a bit of hum in it's mod, but no distortion. I would recommend taking a look at them and replacing any suspected as being paper - even if you can't recast them, for now.