My original 1976 I bought in 1975 only had a lab belt, and it was a K-10 Custom Deluxe with 6200GVW. But it did have the bolt holes for a shoulder belt to bolt into the pillar. In 1976, the GVW 6200 was considered Heavy Duty. However, I have a newer 1976 now and it does have the same GVW rating...