I'm unsure about the early (first/second gen. CD player) Sony DACs' internal architecture -- but the early Japanese CDPs had no oversampling.
That said, ... R2R dacs used for digital audio playback (made by Analog Devices, Burr-Brown, et. al.) FIRST came into application well into the age of dedicated-IC oversampling. One could even speculate that Analog Devices, Burr-Brown, et. al. INTENDED their DAC ICs to be used
with oversampling.
Some of the early enthusiasm about the "goodness" of NOS (which began with DIY projects like
http://www.dddac.de/ back in the late 1990s) were centered on using classic Philips DACs (which are not R2R
,which are not R2R!!) -- simply bypassing the OEM digital filter IC (e.g. SAA7220).
Hence much of the mythos and DIY NOS culture is based on NOS DEM .... not NOS R2R. So why would NOS R2R -- Denafrips, Holo, etc -- have the "NOS" sound?