I believe the Custom Seat Program started in 2008.
Select Pattern, Inlay Material and Stitching Colors in 800 Possible Combinations
A new Custom Seat Program from Harley-Davidson Genuine Motor Accessories lets a customer design a leather seat that is hand-built to their specifications. Available for the solo Brawler seat (P/N 52246-08, $399.95) or the two-up Sidekick seat (P/N 52193-08, $479.95) designed to fit most 2006-later FX Softail models and 2007-later FLSTF Fat Boy and FLSTSC Softail Springer Classic models, the Custom Seat Program offers 800 possible design and materials combinations, making it possible to create a seat that is truly individual.
The design process begins at the Custom Seat Program website,
Custom Seat Program | Harley-Davidson USA, where on-screen prompts help the customer select from two seat styles, eight stitching patterns including flames, skulls and tribal designs; eight inlay color options; and 10 stitching color options. When the design is complete, the customer takes a print-out of the seat design details to a local Harley-Davidson dealer, which will submit the Custom Seat Program order. The standard lead time for seat delivery is three weeks.