"The blackbody equilibrium temperature at 1AU from the sun is about 278K. All satellite materials are fine at 278K because that's within the expected range of storage and atmospheric launch temperatures."
But that is NOT the temperature of something in LEO. You're ignoring everything else that adds energy to the system. Friction from collisions with atomic oxygen, down to heating up to temperatures as hot as 530 Kelvin just entirely dependent upon orientation to the sun.
My impression is that friction is negligible once firmly in LEO. Orientation of a sub-component surface definitely matters, as does Earth's presence in half of the viewshed. But my point is that surface finish also makes a big deal, and paint is not necessarily a bad thing, because of the emissivity increases.
(Though I'd rather anodize the thing black imperfectly if it helps avoid paint flecks becoming orbital debris)