Essentially all current D/A and A/D converters use oversampling and 1 bit conversion (Delta-Sigma, which is what SACD is based on) as their basis of operation. Whether the digital signal is "upsampled" to 192/24 or not is a moot point since the data is oversampled anyway.

That being said, upsampling to 192/24 or 192,000/48 for that matter is not going to give plain old 16 bit 44.1k (or even 24 bit audio) audio any more resolution that is already contained in the file. You can't add resolution that is not already there.