The question you have about making sure the wires land exactly on the proper networking terminals is probably a better question to be asked of the technical support for each panel model you are working on.
RS485, as a wiring system, looks simple, but each panel model is set up a little different, so technical support would be the best people to ask.
Labels on wires are fine, as long as they can be read. If the letters are rubbed off, the labels just get in the way of servicing.
Good options for the labels come in two varieties:
- Labeling Machines: The labels look good, but care must be taken in choosing the machine type. Overall costs are greater, and the fragile machine requires care as it is being dragged around by the installer.
- Cloth Tape: The labels looks ugly, and care must be taken in choosing the tape type. However, the writing put on the tape using sharpie pens NEVER rubs off, and when comparing costs to a labeling machine, tape is cheap, and the installer can carry the roll of tape all over the place, without the concerns of accidently damaging it.
The company I worked for uses P-665 Gaffer Tape. This tape, used for labels, can be dragged through conduit without a second thought, and after 30 years, the tape is still readable. (OK, 40 years, but who's counting).
Both options are used by the company I worked for, which one is used depends on what the labels are being used for. The company I worked for never used white electrical tape for labels because... the writing rubs off.