[morzh]

Your 2800 ohm is ok, it is in parallel with the 500 ohm resistor so it results in 424 ohm (435 is close enough).

1.4M instead of 1M cannot be explained by connection, but then it is treble resistor, I doubt the tolerance does anything to the volume level.

Try to see 33K and 15K resistors from the anodes of the 2nd Audio tube, poke around the tube itself.
Make sure you did replace the capacitors ##82 and 136.

You're lucky - I had to re-cone both tweeters and wanted to re-cone the woofer but ended up patching it. Big gaping hole due to the broken wooden cone attached to the front panel that fell and tore the cone.