I think the 1300
used a single DAC rather than the twin DAC
of the 1500. That was way back when DACs were expensive and only top models got two. That whole series had mediocre reliability as I recall. The later Mk II and 20 series were a lot better.
I just picked up a Mission PCM II, almost mint with remote, outer and inner boxes, all packing and transport screws for $90. We sold both and the Mission killed the Denon. Also, the Mission is much less common which means they command a fair amount more. So yes, $75 seems high.