Whether it be 277/480, 120/ 240, or 120/ 208 V.A.C., do conductors need to be indentified at LB's?

How about neutral wires in LB's on a 120/ 240 residential service?

I'm going to guess no on your first question unless you have conductors of different voltage systems.Meaning 277/120 in the same LB. Read 210.5{neutrals included 200.6(D)}
Neutrals should be white unless they're no #6 or larger, which then the only need to be identified at termination points 200.6(B).

I asked about the 277/ 480 thing because of a job I was on today where none of the conductors were not identified in a trough. They weren't terminated there either. I've had an ongoing disagreement with one of the other guys at the company about identifying neutral conductors at an LB on a residential service. I never had to idnetify them in the past, why all of a sudden now do I need to do this now?

I believe the code requires the neutrals and grounds to be marked wherever they are accessible- which, strictly speaking, would include LB's. Yet, I've neither seen this done, nor seen it enforced.

Now, were there splices made in the wires, then marking them seems to be "common sense."

One of my only 2 gigs in 10 years has been for not having coductors identified in an LB.

Jim what do you mean by gig? Failure I assume. I've only heard that word in reference to a job.(ie that would be a nice gig to have)

Sounds like a Navy man to me.