I just looked up the Vintage Trek web site and apparently in 1987 there were two versions of the 560, the plain 560 and the up scale 560EX. Both used freewheels with the 560 having Sansin hubs and the 560EX using the Shimano 6208 under discussion. The regular 560 had 105 6-speed SIS indexing dt shifters and a compatible 105 rd while the 560EX upgraded to 600-series components, also 6-speed indexing. Here is the link to that catalog:

http://www.vintage-trek.com/images/t...rekCatalog.pdf