this is one of the best treble boosters I've built and I've built alot of them being a Brian May fan.
this was traced from the circuit board and I have made 2 changes (that don't affect the sound)
1. in the original there are 2 power supply capacitors (47uf and 33uf) in parallel which was obviously used to keep production costs down - Greg will have initially put in the standard 100 uf capacitor but if his other pedals/products used 33uf and 47uf caps - it would have been cheaper to just parallel a couple of those up to get near enough.
2. the other change is that there are 2 10pf capacitors in series again this will be a production cost thing - it would be cheaper to use 2 10pf capacitors in series than adding 1 4.7pf cap to the build (if he used a lot of 10pf capacitors in other builds which he most probably will do.)
so with those changes noted: it sounds no different to the original unit but you can always swap them if you don't believe me.