Every case has them but the old ones may be 2 or 3 separate connectors.
You can download the Motherboard manuel and find the pin assignments. Frankly for a gaming build all you need is the two wires to make the sound work, the others for recording your voice you don’t need
If your using HDMI and you speakers are on the monitor you may not need them but not so sure on that.
Most MB’s are pretty well labeled on pinouts and stuff