According the the Rebate .pdf file, the rebate is only valid for upgrade customers. The rebate form states:
"Enclose proof of previous ownership of Norton Antivirus for Windows by furnishing product CD, diskette 1, or title page of manual."
However, the rebate for also lists:
"This offer is valid only for standalone, full version purchases of Norton AntiVirus 2000 for Win98/95. Offer not available with site licenses, NFRs, OEM, 10 packs, resellers, or academic offers. Offer is good for one person per organization. No Products purchased at an upgrade price will qualify."
To get the rebate you must already own Norton AntiVirus. So, you basically have to purchase an upgrade. However, no product purchased at an upgrade price is eligible for the rebate. So, you have to buy an upgrade at a full product price in order to get the rebate.
How this effects the rebate, I have no idea.