In the original the buzzing bass subvoice is definitely stronger than in both your examples. It is more a bit like a slapbass or plucked ruler humming in the background (or a low organ footage). But that is also because your pitch (clock rate) is 1 note too high (your "D" note is my "E", so I can't reach your "E").
Your sfx_r7_2700.wav example sounds closer, but R7 definitely is red-violet-red-gold.
With the Coleco Galaxian tabletop I suspect that they used a VCO with analogue fixed falling pitch envelope generator because the chip would have been incapable to compute the stepless howl without wasting too much CPU time.
