Jammer, not familiar with any special badged '99 W140 model. Others may know of one.
On the Coupe, they were simply marked S500/S600 in the North America market up through 1997. In 1998 and 1999, the W140 Coupes were marked CL500/CL600, putting them in common designator with the Euro market, where they were always sold as CL500/CL600. Additionally in Europe, there was a CL420.
Bottom line is that if you want a W140 Coupe, made in 98 or 99 (almost identical cars), look for a good CL500.

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KenP

1996 S500 W140 Coupe