So, does the IoM use ZERO automation?

So, I read that factory lines are completely manned by manual laborers that build thinks like lasguns and tanks completely by hand. Is that true? I get that the imperium (especially admech) DESPISE the use of AI. I also know about servitors, but are they accurate enough to be a suitable substitution for precise construction? Just wondering where the line starts with pure human construction to servitors to something pure machine.