The tank, seat, skid plate, and flag mount are off of a 2001 KTM 520, and should also fit similar year 400, 525, and 540.
Bought new and hardly used KTM tall seat, part # 59007040000 $90
Bought used and never used 13 Liter 3.4 Gallon OEM tank, no petcock or cap, #59007013200 $80
Third item is a HRF flag mount, part number 3001 08, said to fit most 1998 to 2010 KTM's, list at $49, like new used $20.
Fourth items are a pair of OEM KTM 18/21wheel assemblies I bought new for a 1997 KTM 620 EXC LC4 chassis to have a set of more streetish tires ready to go when needed. These wheels are complete with AVON Gripster AM24 120/80/18 and 90/90/21 tires, both rotors, 40 tooth sprocket on a cush drive, uses a mechanical speedometer drive, or a fitted spacer for without. Older tires, the set was used less than a few hundred miles and have been in dry storage for about 23 years, $650 for the complete set. Unlikely available from KTM, but newer like wheel assemblies would run about $1,100 for a complete cush drive rear, and about $800 for a front.
Last item is a K Style aluminum skid plate, $20
If the ad is up, they're available, so inquiries asking "if available" and or without a phone number will be ignored. I don't text, and with limited time emails won't be answered without a contact number. So, a phone call is best for a prompt and accurate response. John at 53ZERO-477-71FIVE8