The only number I can see, that may be a part number, is 2586 on the bottom of the screw cap.
HARLEY DAVIDSON SPLIT PETROL TANK
99539-97 Harley-Davidson® Fuel Cap Medallion - H-D Motor Co. Logo
(u1) OEM Harley Davidson Fuel Cap Brushed Satin Sportster XL 1200/883 #61289-07D
Harley Davidson Fuel Tap Petcock Strainer Filter 9/16 or 14mm UK MadMopeds
Harley Davidson Fuel Oil Line Clamps 7/32" to 5/8" BT & XL Stainless Steel
NEW CHROME PETROL FUEL TAP FOR HARLEY DAVIDSON PETCOCK CUSTOM TANK ARMSTRONG MT
