N1711Q is well into that age, built in 1982. When working on damaged areas
we sanding carefully to expose fiberglass in several areas. It looked very
good. That's a single data point, but it falls in line with similar repairs
on Velocities which are constructed with similar technique and materials.
For a plane stored in the sun the answer may be different.
I've seen awful messes for planes which were parked outside without primer,
or thinly primed, and became dumpster bait. I would not consider repairing
any surface in that condition.