Are you sure that the low pass behind the interpolation stage in an upsampler can be called reconstruction filter?
Pretty sure.
Only the very first CDplayers (no oversampling) had steep analog reconstruction filtering. Philips and later designs that had oversampling had part of it in the upsampling filter and a less steep analog reconstruction filter after the DAC.
This was possible because the DAC always operated at the same freq. 44.1 or its multiples.
Current DACs need to have a variable frequency filter for each different sample rate it would need to shift frequency to Nyquist.
This is practically impossible to make with pure analog reconstruction filters.
Digital and or switched capacitor filters can do this.
In case of OS DACs the reconstruction filter is in the oversampling part (as to not get mirror images) which should be steep to work well.
The question could be at what point (frequency) one can still consider it part of the reconstruction filter.
The oversampled output (in case of R2R) can be less steep and only need to 'smooth' the signal (partly reconstruction one could say) so steps are gone.
For DS that output frequency is yet much higher and the post filter only needs to remove the non essential noise.
In this case, AFAIK, the output is not DS (with a few bit levels) but a DSD stream (1 bit) at a very high frequency.
One that doesn't pass the transformer anyway and an extra capacitor is used so the transformer doesn't get much HF to begin with.
So only 'post filtering' to remove DSD switching frequency, which for DSD doubles as a reconstruction filter.
Don't know this for certain (that PS works that way) but is what I would do if I wanted to design in a similar way for some reason.