What you are obviously oblivious to is that SGMO tested the genetic modifications by the ZFs to see if they worked. They did. The ZF modifications also worked in SGMO's two HIV drug trial.
KBLB did not test the GMs because doing so would have required a tissue sample and they didn't want to risk the worms. But if KBLB's ZF GMs failed to achieve the desired results (or any other SIAL customers' GMs failed to achieve the desired results, the GMs would be directly tested after that in cases where they had not been tested beforehand. When altering millions of immune cells as SGMO was doing you just remove a few to test; if doing a large transgenic animal like a pig, cow, or goat, you just remove a few cells. But for smaller animals like silkworms that's a risk. If it accomplishes the desired result, no need to test. If not, you test because it is imperative to know what happened.
It is, of course, possible that the GMs on the silkworms will not have the desired effects (as I had often noted). However the fact that the Monster Silk worms have already produced silk containing ~67% spider silk protein rules out most of the possible causes of failure, so the chances of success are very good. If a failure does occur it is unlikely to be because of the zinc fingers not achieving the desired genetic modifications. However that does occasionally occur (usually due to "off target hits") but it's easily remedied by "tweaking" the zinc fingers to weaken their grip a bit so that they still bind to the intended target but not to the unintended one.
Note that I very explicitly stated here a number of times before that GMs did not always have the expected results even when they were done correctly. And that is exactly what happened in the SGMO SB509 trial. The risk for that was far higher in the SB509 trial. In the KBLB GM, the hard part, inserting a gene to get spider silk protein produced in the silk, has already been accomplished. The rest is by far easier. That's why the risk is far lower than it was with SGMO.