I tend to think that his 'case' couldn't really hold up.
An as-built, in it's minimal state, is nothing more than a documentation of things that are added or deleted from contract drawings. While many of us who do them may include important J-box locations, and other 'secrets', that, IMO, isn't part of the contractual requirement. The requirement of the as-built is more to cover the 'there's 6 lights instead of 5, and they are 60 watt instead of 40 watt' type thing.
So, saying that, it would seem that any competent electrician/foreperson could walk a job, review documentation, etc, and produce a reasonable set of as-builts.
Personally, if it was my company, I'd throw it together myself, even if I had to 'wing' it a little.
The company chose to not have someone do that, largely in part of the extreme incompetency of this organization, which is why I left.
I think the only thing that might work against me, is a judge who has no understanding of construction, it's practices, or what as-builts are. He would view this as an 'outsider', which might place more sympathy on the side of the employer.
Either way, this former employer is guilty of not paying into any employees IRA accounts for two years, a mandatory 2% of incomes.
He makes statements like " A raise? That's a good way to get fired", and so, I have no desire to cooporate with him.
I am going to make an 'offer' to resolve the matter. If he wishes to re-hire me, I will agree to work for him temporarily, as a sub contractor for a reasonable hourly rate, plus enough to cover the taxes on it, plus a few dollars an hour more to compensate for the benefits. Then he can 1099 me next year, but I'll already have the taxes on it paid by him.
Plus I want my IRA money before I do anything.