I owned an HQ-170C a few years back. As I recall, the small capacitors were
most or all ceramics, so you won't have to replace a bunch of leaky paper
caps.

I would recommend replacing the electrolytic capacitors, however. After
about 40 years, they are probably either shot or about to fail, whether or
not the set has been used. And the consequences of a power supply failure
can be expensive.

This article gives some basic information about recapping:
http://antiqueradio.org/recap.htm .

Especially if it has been sitting unused for years, the receiver will also
benefit by cleaning of the controls with a good spray cleaner such as
DeOxit. Don't forget the bandswitch.

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html