Hi,
I wish I could see more details - such as headset details, type of tubing used for frame and forks, handlebar and stem identity etc. - but from what I can see, the bike looks absolutely beautiful - a stunner - the only bits I personally do not like are the saddle and the seatpost.
I think the bike is probably mid-seventies - the inner chainring looks like Campagnolo 753 which was made for the Campagnolo 1049 chain/crankset, which was produced in the mid-seventies. I can not identify the pantographed outer chainring (which looks fantastic) but you can try your luck by trawling the Velobase site (
http://velobase.com/SearchBasic.aspx)
Did your father buy it from new or did he buy it second-hand? I have a suspicion that the chrome on the main frame tubes (not seat stays and chain stays)
may have been applied as a later upgrade by a previous owner,
if your father bought it second-hand.
As another member has said, it is worth whatever people are prepared to pay but looking at the bike and the details I can see, I would definitely say that you should not accept less that €1500 and it could well be worth much, much more -
all the way to the bank.
Colnagos in good shape are sold on the bay for prices that go from €1200 to €3000, depending on the model, groupset, paintwork and so on.
I wish you all the best with the sale - unfortunately my old age pension will not stretch so far
