But a very few - a limited edition - were released with a glass roof.
The two roofs were completely interchangeable and during those years, replacements for the glass part were actually made by Pilkington Automotive for aftermarket company Saratoga. But Saratoga is no longer in business and the part is no longer being made - or wasn't, until early in 2013, when a Porsche 944 owner made contact with Pilkington Classics to find out where he could get one. Less than eight months later, he drove away with it. And scores of his fellow Porsche enthusiasts have since followed suit.
"This was a genuine grass roots Pilkington-consumer effort," said Matt Lane, Operations and Sales Manager for Pilkington Classics. "We would never have made the part if the owners had not come to us.
"They worked alongside us both here in Columbus, Ohio and in Northwood, Ohio, where the tooling was developed. They loaned us their cars to develop the part in the first place and then one local individual, Jason Penczak, tested the part we came up with.
"He'd had one or two issues with wind noise and rattling on his old roof and so we refined the latches and the seals to give a good fit and better insulation."
Pilkington Classics obtained the original Saratoga trademark and trademarked the Saratoga Top® name, in order to give the part complete authenticity, and liaised with the Classic Car enthusiasts' website Rennlist throughout the development process to obtain feedback and flag up the release of the part.
The glass roof is now selling well in the US and a distribution operation for the UK and Europe is being set up. "The glass roof has been quite a hit," he said. "Thanks to the Porsche drivers themselves, we now have a very successful addition to our catalogue of classic car glass."