Nevada authorities said two San Francisco men are in custody in the disappearance of $187,000 which fell out of an armored car in San Francisco Aug. 13. Jeffrey E. Feltman and Clinton S. Robinette, both 22, were charged with possession of stolen property and forgery. Bail was set at $7,000 each. They were arrested Friday at a Lake Tahoe casino as they tried to cash an undetermined amount of travelers checks. Sheriff's deputies said the American Express Co. checks were part of the materials that fell out of the armored car when it rounded a street corner and the door flew open.