My '79 Marshall JMP 2203 - reckon it's stock, or modded?

Here's the guts of my '79 JMP 2203 posted at TGP.

https://www.thegearpage.net/board/index ... t-25663946

This amp seems to me to have a boatload of gain - I'd like to get some more old school open clean out of it.

I'll go through the schematics and layouts, but in the meantime, anyone really familiar with these circuits who could possibly identify if anything isn't stock would be giving me a great starting point.

There's a couple empty slots on the pcb and that piggy backed carbon film resistor.

Cheers.

Bright cap is back in.
So much better.

And I pulled out the cathode bypass cap. 330uf.
So much more clean headroom.
Still gains up to early Van Halen up around 4 o'clock on the Preamp knob, which is what I want.

It's modded. Can't make out all the values, but it looks like a Jose type thing or a 1 wire type thing that was done to super leads.