Question:
Will an airplane with a NACA 2412 airfoil make a decent slope glider?

Crash

With a favourable wind, a plane with a shingle for a wing will make a decent sloper. Tex.

the 2412 is a good old fitzall shape -which is thick enough to build with good strength
done right as good as any
the "super duper pooper slope guys may say other shapes are better - but if you are building the wing -this is a good one

It won't be super fast but it'll do nicely on a sport sloper or on a PSS style.