FYI ...
The particular, aluminum framed Colnago dates from ~2001 (I believe that's when the downtube derailleur cable guides superseded downtube braze-on mounts on most Colnago frames ... the exception being the steel Master X-Lite) ...
The Shimano Ultegra 6503 group dates from the same period ...
[INDENT]The LBS/retail cost where I live would probably have been about $3000(US) +/- with the unknown variable being the wheelset.
[/INDENT]
BTW. Based on the appearance of the teeth on the Chainrings, Cogs, and Pulleys (all of which could have been replaced at some time, but I'm going to presume they are the original components), I reckon the bike has seen less than 6000 miles of use.