Yes, you need to enable both if you're planning to use
font-weight regular in some places/text and
font-weight bold on some.
After you define the font-families that you need on Font Manager, then navigate to Theme Options > Typography, there you'll see the BODY FONT, BODY FONT WEIGHT, HEADINGS FONT, HEADINGS FONT WEIGHT
The posts metadata (pink text) in part of the header, so it will inherit the heading font configuration.
Hope it helps,