nope ... removing D5 leaves D4 in circuit ... they're in parallel ... taking them both out would give you a big volume boost as you describe as there would be no diode clipping just opamp gain/clip ...
I know who "nameless" is 
I popped the hood and double checked, yes, I'm just disconnecting D5 and leaving D4 stock. I thought I was removing both from the signal path for the booster mod I've read about, but I'll take your word for it that I'm not. But, yes, there is still a volume jump.
Anyway, I strongly recommend trying this mod. Again, you only need to remove D5 and set D4 as stock (assuming many have an added LED in series with the stock D4 diode, which may sound good as well). With a high distortion setting, this mod gives you a similar fast attack, compression and treble grind as when using an LED in D5 and stock D4, but the bouncy note bloom and heavy distortion are fairly removed. The remaining tone kind of reminds me of the MI Audio Tube Zone I recently had, but I think it's even better in that it's more radical in terms of coloration ... it's pretty thin with an almost synthetic type grind, what I consider "boutique" sounding. Awesome with my Strat through My JCM800 clean channel. Give it a go.
One question regarding the other "popular" options. Am I missing out not having the high-gain mod with added LED in series with stock D4 (when D5 is with the LED)? I tried this and didn't like it because it was too muddy, but now I'm wondering if this can do more in lower distortion settings, adding tones that cannot be had with D4 as stock. In other words, if it's only adding gain at the top of the dial, I'm fine without it.
Thanks.