It definitely
was getting too much fuel which is why they disabled the old pump. The mechanical pump was no longer functioning well enough (due to a worn cam) to pull on an empty line but once the electric pump primed it then the old worked too. They removed the arm from the mechanical pump to stop the pumping action but it is still part of the fuel pathway. The old pump is now basically a non-functioning piece of metal there (sort of a glorified plate). I was wondering if the fuel hose can't now simply bypass the whole lot and go straight from the fuel filter to the carburetor? I guess the only reason for leaving it in its present setup is in case the mechanical pump needs some fuel inside of it to even function as a plate, or I can't find a plate to fit (this car place only replaces stock parts which is why this job was a bit of a challenge for them and they may not have a toolshop).
Standard tools I have, plus Haynes and Toyota Shop Service manuals. Unfortunately none of my friends or family know, or wish to be in any way involved in, automotive projects, so I really depend upon feedback from places like this and have to feel confident
I know what is wrong and it is something
I can manage 100% on my own. I do some minor work on the cars (I actually have two '81 wagons) myself (radiator replacement, plugs, alternator, distributor cap, wires, belts) but I am limited by not having a good way to work on anything requiring getting under the car, car knowledge outside of what's in the manuals or I get from the web, place to work on the car, or a true workshop. The car with the pump issues isn't too bad (particularly for a 33 year old car in Minnesota) but the other one (destined to be a parts car the next time something costing more than $200 happens to it) is very rusty, been rear-ended twice, and I don't know if I can get it up on jacks any longer. I have a set of car ramps but the last time I used them on our asphalt drive I noticed two deep gouges in the drive where they had sunk in on a warm day (the same might happen with a jack). I realized I was under the car when that took place and prefer not to do so again! Ramps also don't work if I am trying to get the back end raised.
Oh, count out doing anything between late October to mid April when you
do not want to be doing something finicky outside all day in Minnesota!

That goes double if it involves lying down on ice covered drives.
The only thing you can really see is the pump and you can't really see that. I took one very bad photo (hard to get visual orientation) by sticking my arm under the car and blindly taking a shot. I'll see if I can get some better ones the next time the car is out of the garage and I can lie down next to it.
In the for what it is worth department, I took the car in two days ago (wasn't hearing anything on the forum here so didn't know what else to do) but the mechanic there didn't see anything wrong and didn't know why it was knocking at idle (though as I said, I kind of get the feeling I know more about this than he does). It only happened on that one occasion when I had been driving freeway speeds and came to the stop and go scenario for 15 minutes. I have to stop for 2 minutes all the time at traffic lights here but don't get that kind of noise.
I'll consider getting the lower rated pump. The guy at the local NAPA (who looks old enough to be familiar with this age car) recommended this one, but I called a different NAPA and the guy mentioned a 2-4 psi which I am now hearing here might be a better one. Not sure if I can get them to take the old one back now that it has been in the car for 6 weeks (this car gets driven about once a week, about 15 miles each time).