Yes, it means 'serdeczny' but is used in different context.
You can say:
a hearty welcome
a hearty meal 'obfity posilek'
a hearty appetite 'dobry apetyt'
he sang in a hearty baritone
he has a hearty and boisterous character
he expressed his hearty agreement (of a feeeling or an opinion)
a formidably hearty soinster of fifty-five (of a person - strong and healthy)
There's sth like greets 'me hearties' -a form of address ascribed to sailors.
I've never spot and hear "hearty regards'
but not 'hearty regards'!!