Doh! I totally forgot about C7!
I'll try to measure it tomorrow but I suspect I won't get a reliable reading in-circuit. If the pedal was mine I'd dissect it and measure em all out of circuit.
I've also seen conflicting values for C7, but here is a quote by Mark Hammer that might give a little insight.
If you are going by the old Boomstick document at the Madbean site, then there may be some issues with the parts values. The document I'm looking at has the components on the bass side as 47k and 22nf, yielding a treble cut starting around 154hz. On the treble side, the values shown are 100nf and 82k, which yields a bass cut starting around 19hz, which is pretty much no bass cut at all.
If you made that cap .01uf, instead of .1uf, that would shift the bass cut upwards, so that it starts around 194hz, which is complementary to the treble cut.
If we're extremely slow at work tomorrow I might try to pull the two capacitors in question.