That is very interesting. I think the third transistor is a bc183c though. it doesn't make much sense as it is but with the base going straight to ground it makes zero sense to me. EDIT: you might be right and this is a bc169c?
I made a simulation of the circuit on Falstrad.com/circuit you can copy the below into a file with FILENAME.circuitjs.txt to upload my circuit.
I found that grounding the collector capacitor (this is the one that looks to be grounded in the AM photos) means that when the fuzz pot is in a very specific place the third transistor will cycle through three phases, cutoff, forward active, saturation. While as before the transistor would be static, it would be saturated or cutoff depending on the fuzz pot. To get this cycling though you do need a very specific value of fuzz. (around 77Ohms).
Here you can see a nice low input voltage a cleanish signal
Fuzz up and distortion
Then this is the settings where I was able to get some movement from Q3. Grounding the over cap means that the base sees zero signal and I can't work out anywhere for them to go (all I can think of is that this cap went to a switch to turn on/off the third transistor and I have zero idea about the transformer/inductor)
Below is code for Falstrad sim
$ 1 0.000015625 1.3241202019156522 61 5 50 5e-11
r 304 224 304 176 0 4428.46
r 304 176 304 128 0 330
w 304 128 224 128 0
c 304 176 432 176 0 1e-8 8.66600527355504 1
g 432 240 432 256 0 0
R 224 128 128 128 0 0 40 9 0 0 0.5
c 160 256 96 256 0 0.0000022 0.556889757543908 0.001
w 512 384 512 336 0
w 512 416 512 448 0
r 224 128 224 224 0 33000
w 304 272 304 320 0
174 304 320 304 400 1 1000 0.5990000000000001 Fuzz
r 192 320 304 320 0 100000
t 160 256 224 256 0 1 -0.5801399385092704 0.5581699359854974 60 default
w 160 256 160 320 0
t 224 240 304 240 0 1 -6.343174082990598 0.5660080940530058 120 default
w 224 224 224 240 0
w 304 256 304 272 0
w 320 368 336 368 0
w 336 416 304 416 0
w 192 320 160 320 0
r 512 336 448 336 0 1500000
r 432 400 384 400 0 10000
w 384 400 384 368 0
w 448 352 448 336 0
w 512 448 544 448 0
l 544 448 608 448 0 0.55 0 0
174 432 176 432 240 1 100000 0.005 Volume
w 448 208 496 208 0
s 336 368 384 368 0 0 false
t 464 400 512 400 0 1 0.2981800032635263 0.3776252510810153 100 default
209 448 416 448 464 0 0.00001 0.000999999999980128 0.001 1
w 432 400 448 400 0
w 448 400 464 400 0
w 448 416 448 400 0
w 448 352 448 400 0
s 48 256 96 256 0 0 false
R 48 256 -16 256 0 1 366.4 0.0028000000000000004 0 0 0.5
209 336 368 336 416 0 0.000019999999999999998 0.37973658068842925 0.001 1
w 512 448 512 496 0
w 304 496 320 496 0
w 320 496 512 496 0
w 224 416 224 496 0
w 304 496 240 496 0
w 224 272 224 384 0
g 224 496 224 512 0 0
209 512 336 608 336 0 0.00001 0.000999999999996573 0.001 1
w 304 496 304 416 0
w 240 496 224 496 0
w 224 416 224 384 0
o 28 4 0 xc1012 0.07691538964795755 0.0001 0 4 1 0.2 0 0 28 3 0.000049999999999999996 0 0 37 0 0.1 -66 0 37 3 0.000025 0
38 0 F1 0 1 8200 -1 Bias
38 37 F1 0 0 0.04 -1 Input\svoltage
38 37 F1 3 10 1000 -1 Input\sFreq.
