As a starting point, you might want to compare what you have with what's available at sites like B&H Photo's used dept. - http://www.bhphotovideo.com/c/browse...1/N/4294247179
or KEH - http://www.keh.com/onlinestore/home.aspx
both very reputable dealers. Understand that the price other examples are selling for, is going to be a bit more than what they'd offer you, but it'll give you an idea.