dark saddle v. med or light saddle

[Bill72]

Looking for some clarification on saddle interiors. I thought dark saddle was a 72 only thing. Classic Parts lists dark saddle seat covers for 71-72 and light saddle for 67-70. (No pictures) Then they show dark saddle door panels for 70-71. So my questions are: was dark saddle a 72 only thing? Do the after market guys now produce 72 seat covers and door panels in both light/medium saddle and dark saddle? Thanks for any light you can shed on this.