Joe, sometime in '73- early '74, DeTomaso stopped using separate shoulder harness that could be unclipped from the lap belt, and began using one that was permanently sewn onto the factory seat belt. Those belts used an extra shoulder harness retractor that was mounted in a recess in the firewall on each side. So the 'late' bulkhead cover has large canted rectangular holes in them while the early type for two piece seatbelt/shoulder harnesses has no holes. You need the early version for your '71.
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