The 230SL used a basketweave insert; later models used a pinhole pattern. Make sure you see a sample of the insert as well."
No, that's not correct or let's say not accurate for the leather (I think that is what you are heading for).
While the Vinyl seats (MB-tex) are indeed different (as pointed out in the previous posts above), the leather is definitely not.
It always carried the basket weave pattern, earliest 230ies until latest 280ies,
which is of course not as "coarse" as on the vinyl seats.
However, with the years and (perhaps heavy) usage, the basket weave pattern "wears off" until nearly only the holes are visible. But in hidden areas (e.g. where seat cushion and seat back lie together the "untouched" basket weave pattern is certainly intact (virgin).
BTW, the today available pattern e.g. by GAHH is too strongly accentuated; it was less with the Originals like Jon Bernadi's car.
Good luck & keep us updated,
Achim