Depending on the chart the 76-77 is the build year. The build year is August to July. Bikes built from July 76 to August 77 were 77's. July 77 to August 78 were 79's and so on.
Your 447-724328 is a 77 XS650D US model. Sometimes dealers sell a left over bike and title it the following year. This may have happened on your bike. As long as the VIN matches the title, I wouldn't worry tomuch about that.
From 70 to 76 they used the 34 mm forks. The first years of the disc brake had the calipers on the front of the fork tubes. In 76 they moved the calipers to the rear.
The caliper can be, with a minor change be used on either side. These were the two piston calipers.
The rotor can be mounted on either side of the hub, except for the very first year of the disc brake.
In 77 they went to the 35 mm forks with the single piston calipers. They changed the rotor offset to match the new caliper.
Leo
Your 447-724328 is a 77 XS650D US model. Sometimes dealers sell a left over bike and title it the following year. This may have happened on your bike. As long as the VIN matches the title, I wouldn't worry tomuch about that.
From 70 to 76 they used the 34 mm forks. The first years of the disc brake had the calipers on the front of the fork tubes. In 76 they moved the calipers to the rear.
The caliper can be, with a minor change be used on either side. These were the two piston calipers.
The rotor can be mounted on either side of the hub, except for the very first year of the disc brake.
In 77 they went to the 35 mm forks with the single piston calipers. They changed the rotor offset to match the new caliper.
Leo