Both D-50 and DV-52 would have Sitka spruce tops and solid EI rosewood back and sides, ebony fret board, and ebony bridge. The D-50 would have the older "domed" or "center raised" head stock shape (sometimes AKA the "paddle" head stock). A DV-52 would have the Gruhn-introduced "tapered" or "snakehead" headstock (tho' the DV-52 was introduced AFTER George Gruhn left Guild). Early DV-52s had a "standard" rosette, while later examples (2001-onward?) had pearl-inlaid rosettes. Early on, the DV-52 was made with a satin finish, while its sibling model DV-62 had high gloss finish and herringbone purfling and rosette. IIRC, the DV-52 came with high gloss finish after the DV-62 was discontinued.
I would expect a '75 D-50 to have straight (not shaved or scalloped) braces from the factory. IIRC, the DV-52 would have scalloped braces. I would also expect some differences in the brace/tone bar placement... compare the '76 D-50 with any of the '94/'95 DV models in the 2nd pic from post #9 in my
bracing blog... the difference in tone bar placement is most evident on the treble side (right side, in this image). The idea was to give the DV models a "vintage" sound straight from the factory...
I would expect both the '75 D-50 and later DV-52 to tip the scales between 5.5 and 6 lbs.
Sonically, I would expect the '75 D-50 to have the typical booming bass and overtones of EIR, with strong mids and sparkling trebles, lots of volume and projection, and an "in your face" presentation. I really liked the tone of my '76 D-50.
Based on my experience with its more blinged out siblings (DV-72 and DV-73), I would expect a DV-52 to have a somewhat more "refined" tone, again with strong bass and lush overtones... just a little "smoother" or "richer" sounding than the D-50.
There is MUCH love for both models on LTG... the DV-52 has often been referred to as the "best bang for the buck" in a rosewood dread.
Good luck!
