Listed for sale is a gorgeous 54 inch Tulip dining table, designed by Eero Saarinen. This particular example has a white base with walnut top. The base is believed to be authentic, though the top was produced elsewhere.  

The table was purchased near the Knoll factory, though the top appears to be a non-Knoll top. Based on proportions and detailing, I would assume that this is a correct Knoll base that was used by a Knoll employee, who had a walnut top produced for the table, though not sourced from Knoll. The top is in lovely shape and is crafted of a quality comparable to that of the Knoll pieces, though the top is slightly thinner than is typical. It does have a beveled edge detail as the original examples do, though not as deep of a beveled edge. Given that many of these pieces were made with white laminate tops, it is also possible that the original owner wanted to upgrade to a wood top without sourcing it from Knoll directly.  

The base appears to be vintage and looks lovely. Condition overall is very good to excellent for a vintage example.