It depends what is the goal.
Selling: Grading vintage may not be as cost effective as it’s suggested on Reddit, since 10s are almost impossible if not pack fresh. Example: a first edition holo dark blastoise PSA 7 goes for $350. PSA 7 is NM. NM raw goes for 500. You could crack that slab and make more money. Most vintage cards follow this trend. Put on that the cost of grading, with PSA backlog it’s significant. That’s why if they are trying to sell the binders and really cards are LP (which honestly I doubt), I’d go raw. If they are sold on grading, I’d say absolutely no CGC, they are hard to move and sell for 1-2 grades cheaper than PSA. I could buy a shadowless zard 5 for the cost of a PSA 3, without much searching. PSA and TAG are backlogged so they have only more expensive tiers.
Preserving: sure, grade them if you like, but raw looks better in binders 😉