[Arran]

It's very easy to get the filter cap wiring mixed up on one of these early to mid 1930s sets if you aren't careful. Not only did they used to use different grounding points for each cap sometimes they had the positive side tied together with the speaker field coil on the negative side. In some cases they would have a single cap in one can and a two or more section cap in the other, the Rogers Ten-60 I am working on was wired this way. Many time the innards of the filter can had no connection to the can itself.
With regard to the resistors you can usually test them in place, unless that resistor happens to be connected in parallel with a coil or another resistor. When it comes to replacement if they are within 20% or better of what they are supposed to be I leave them, with the exception of ones that are normally buried and inaccessible without tearing the radio apart, like some of the ones are in my Rogers Ten-60. If the volume is low one common think that can fail is the plate resistor on the first audio tube, sometimes they used a 1/4 Watt where they should have used a 1/2 Watt.
Regards
Arran