This hotel opened as the Puerto Rico Sheraton in 1963. It became the Dupont Plaza in 1978. The Dupont Plaza never reopened after the New Year's Eve fire in 1986. It was to reopen as the Palm Hotel and Casino, but they were denied a license. Eventually it reopened as the San Juan Marriott and is still open today.

The Puerto Rico Sheraton

The Puerto Rico Sheraton on the Caribbean ChipGuide
http://www.caribbeanchipguide.com/chip2.php?primarykey=PROSHR&sort=type

Please note that you can check the lineage of a casino on the Caribbean ChipGuide through its history. At the top of the page listing all the chips and other items from the casino there is a Casino Information box. The top links in the box are for "WAS" and "BECAME". If you click on these links you will see the the previous or next casinos in the lineage.