With all that said, good job on the repair nonetheless!
Thanks for your comments.
Here's a microscope pic of several items for comparison.
From top to bottom -
SMD 1206 zero ohm
original 100 ohm Boonton part
Same as above
original 160 ohm Boonton part
The 1206 part is very close to the same length as the resistors, which is the reason I chose that dimension SMD.
The original problem was that one of the 100 ohm parts (red part) was cracking loose right at the solder joint. Why this happened we can't say for sure. However, these parts are decades old and I'd bet money they haven't been touched or repaired since they left the factory. Only the original damaged part was going to be removed and replaced. However, they were so delicate that they just fell apart at the ends (see red parts in pic). Even the metallic coating came off.
Not to stop there, a 160 ohm part (tan resistor) had one end of it crack off. Basically the sensor was at it's end-of-life. After what - 3 decades, it needed to be re-built or tossed. What caused the degradation in reliability? Was it banged on a table numerous times or were the parts the wrong choice from the beginning (for long-term reliability). I know it was in the hands of Ham radio operators for some time, so draw your own conclusions there.
The point is, the original parts Boonton selected, and the original way Boonton engineers told the assembly line workers to construct the center area of the sensor (the soldering) didn't fare all that well in the long run. What I've done is either going to last for a little while (subjective time) or a long while (subjective time). I don't abuse equipment so I'm guessing a long while (years) but we shall see. I'll test it at least once per year and report if if fails.