Depends on the guitar, the crack and the luthier. Regardless of the specifics, a side crack should be repairable in a way that leaves the guitar structurally sound and sonically intact. Depending on the severity of the crack, laminated sides can be more difficult to repair invisibly, if it's cracked all the way through with the wood pushed out of plane with itself on either side, as the different fibers of the plies don't always like to cleanly mesh back together. That having been said, it can be cleaned up, realigned and glued tight, perhaps with small wood cleats inside. Solid wood is easier to realign and glue up invisibly (not familiar w/ spec on '80s D25s).
Minimum acceptable expectations I'd have, going in would be for the wood to be reglued in a way that's structurally sound and relatively smooth to the touch, though not necessarily invisible. I always tried to have that expectation w/ any crack I brought my guy to repair -- that it'd look just as obvious as it did, going in, but would be structurally sound and smooth to the touch. Sometimes they came out virtually invisible, and other times there was still a pretty obvious crack line. The extent to which the crack disappears will depend on the nature of the break and skill of the repairperson.