That's a bit of a stretch.
The company was founded by other folks (Martin Eberhard and Marc Tarpenning) in 2003, he invested in 2004, joined the board of directors, ousted the CEO in 2007, and was then only able to refer to himself as a cofounder after settling a lawsuit.
Musk didn't build anything "from the ground up," he took control of a company that already existed and grew it into something larger - still admirable, but let's not rewrite history. Musk didn't create Tesla and he wasn't one of the original cofounders.