Check your Trim Tag to see if it was a factory installed option. If so I would keep it as it is a very rare car (I have never heard of another SS with a sky roof).
If it was a dealer installed option then I would say you could go ahead and sell it if you could find a buyer. Not to many people are going to want to cut up their roof unless that exact spot was rusted beyond repair.
"A unique option was added to the Nova line midway through the production year - a sliding fabric sunroof known as the Skyroof. Officially called the Ventura II Folding Sunroof, it was installed on 6,822 Novas in 1972. Each color carried it's own RPO code: White (RPO-WV1), Black (RPO-WV2), Blue (RPO-WV4), Pewter (RPO-WV5), Covert (RPO-WV7), Tan (RPO-WV9) and Green (RPO-YH8)." (There were only 12,309 Nova SS cars built that year and yours was one of the 6,822 that got a sky roof which makes it a small percentage of a small percentage).