bucket seat help

1976 F-body looks different - http://www.hamtramck-historical.com/images/dealerships/colorAndTrim/1976/76_Volare_0005.jpg

1977 is similar, but also different - http://www.hamtramck-historical.com/images/dealerships/colorAndTrim/1977/77_Volare_0010.jpg

1978 F - also different - http://www.hamtramck-historical.com/images/dealerships/colorAndTrim/1978/78_Volare_0009.jpg

The shoulder belt loop may have been added as a custom touch at some point?