Depends on the distance and the type of radar. A typical early-warning
meter-wavelength radar would read these loud and clear, just like, say,
a 747 and a pair of F-15s on the sides - the much hyped "STEALTH"
technology has absolutely no effect on this kind of radar.

With a targeting "microwave" radar things would get more tricky - that's
what these planes were designed to stay hidden from.