He might be able to get away with one that has the plastic snaps. I only say this because there is another forum member that has a 71 280sl (Nov 70 build) and has the plastic snap version.
The change over to plastic snaps might have occurred in the last months of pagoda production. 🤔
His car was purchased by his father and passed down to him. He has no reason to believe it is not original but who knows😜