Built for J.R. Glasscock on a 1929 Packard 626 chassis by the Thompson Products Company, now TRW Inc.
The car currently lives in the Automobile Driving Museum in El Segundo, California. Recent images, including a sign (probably incorrect) showing it as being from 1928.
Information from the museum indicates, it has a 1953 Packard engine, and mentions a 533 chassis instead of 626. Looking at current images and black and white images, there are numerous differences. Features included on the museum car not seen on the original: left side gas filler (previously on top of the boat tail), doors, additional brake lever mechanism (probably relocated because of the doors).
The deck lid (trunk/boot) area previously included the gas filler. The rebuild relocated the filler, so they extended the deck lid. If the museum car contains parts of the original speedster, there may not be a lot of them.