I'm assuming Pawiak is the original building as it was a Nazi "prison" ?
Yes, what is left of it, which is a section of the lower floor.
Images here of then and now: google.com/search?q=pawiak
This isn't meant as a provocative question but are Poles generally indifferent to wartime memorials and museums (perhaps younger Poles) ?
I would say definitely people care, as you will notice fresh flowers and burning candles at all the places of memory, and not only on for relatives. Younger people? That depends on upbringing.
Here are some pics from Powązki Military Cemetery:
The Jewish Cemetery in Warsaw: