I don't know how the pump can be tested, sorry. Other than taking it to a shop.
The weather isn't bad, its cooling down a little. Getting a bit of rain too, so its not all bad.
I hope the ground is starting to thaw up there!
Unless you have a problem with the way the engine runs, I would not mess with pulling the injector pump.I would think that if the pump was leaking enough to put that much fuel in your oil you would notice it in the way it ran.The lift pump leaking would be more probable. And from you previous post, replacing the lift pump was the cure.
The injectoin pumps need shims and and a special pin that you insert into the block. The cylinder that the pump is feeding should be at BDC to have the cam in the right position.There is a difference in the compensating gasket measurements between the B/FL 1011 and the B/FM 1011 so you want to make what model you have.
From looking at the repair manual , It's quite a multistep procedure with a lot of special tools and measurementsn and you should find a shop that can test the pump for leakage before taking anything apart.It can be done if you prep.
If you you do decide to pull the pumps ,I would be curious to see how it works out . I can provide you with the manual procedure but no practical experience.Since I hac]ve two of these engines, I would really like to know if it's big deal to do. just in case. Scott