... if they advertise the thing as having "DSP capabilities" and it doesn't come with a MAC unit, I'd look for a different manufacturer that is more in line with what's commonly meant by that term.

Of course, on modern processors, MAC capability isn't anything special (it's part of the regular ARM instruction set, for example). A "real" DSP should offer a bit more, like hardware circular buffer support, hardware FFT addressing support, zero-overhead looping, or even more specialized things like hardware FIR filter support or hardware polynomial evaluation support.