1968 gts seatbelts

How’s it going folks, my dad recently picked up a 1968 gts 340 and had to put in a new carpet. While changing the carpet he thought that the seatbelts were changed. We looked up a survivor 1969 gts 340 same color combination just different year (light makes right is the tittle on Hemings) and it has red lap belts while ours has black lap belts. What would be the correct color belts for this car. Is there a way to figure out based off the vin or fender tag or do you need the build sheet to determine. We would like to keep the car as original as possible. Any help would be appreciated, thank you for looking.