I think he bears a resemblance to the Bear Mountain Hiker discovered on Nov 8, 1990. Perhaps his jeans had a french-sounding label (Andre Francois) because he lived near the Canadian border?
I have been able to find very little about Grossman that would help -- was he a reader? Did he wear a gold chain? Did he like hiking? Someone must miss him and must know the answers to those questions.
[ame="http://www.websleuths.com/forums/showthread.php?t=68001"]NY NY - Bear Mountain State Park - The Unknown Hiker: Male 30UMNY, 45-60, 1990 - Websleuths Crime Sleuthing Community[/ame]