Such cryptic number-number-letter conversations among Americans always look really pointless to me.
An army should develop its structure, its organization, manpower requirements and then simply train and cross-train the manpower.
That's such a self-evident and general thing that I cannot understand why the technicalities of qualifications attract so much interest.

A small team such as a LRS team cannot make do with specialists only. Everyone needs at the very least to learn the same skills the unofficial way (from the specialist, not at a school).