[NostalgiaRadioTime]

Skip, I've restored 5 of these 1201's. Three 1946's and a 1948 48-1201. Since the 1946 model 46-1201 was sold during 1946 & 1947 (there wasn't a 47-1201), a ton of changes were made to the circuitry during the first two years of production. Ron had posted  ZIP file listing the changes for each code here:

http://www.philcoradio.com/phorum/attach...hp?aid=800

I've never seen a code 126 either, but you can look at the changes between code 125 and 127 to see what is different. The part (external resistor block) in question is indeed factory installed. With regards to your chassis, I wouldn't say it's a mess at all. You're fortunate that it has all of the original factory installed caps. It even appears the electrolytics are the originals. That makes it easier to follow along with the schematic / parts location. The chassis is just "a bit" cramped.