[Fizzlemizz]

If you look at the Garrison UI for the recruiter in your Garrison Inn (if you have one), Blizzard version of a radio uses CheckButtons and:

function GarrisonRecruiterType_OnClick( self )
	CloseDropDownMenus();
	local frame = GarrisonRecruiterFrame.Pick;
	if( self:GetID() == 1 ) then
		frame.Radio1:SetChecked(true);
		frame.Radio2:SetChecked(false);
		GarrisonRecruiterFrame_UpdateAbilityEntries(false);
		frame.Title2:SetText(GARRISON_CHOOSE_THREAT);
	else
		frame.Radio1:SetChecked(false);
		frame.Radio2:SetChecked(true);
		GarrisonRecruiterFrame_UpdateAbilityEntries(true);
		frame.Title2:SetText(GARRISON_CHOOSE_TRAIT);
	end
end

So, nothing "native".

There is the UIRadioButtonTemplate for creating the "dot" button.