Looking for information on Oysterdate Precision ref 6494

[gemupp]

Hi,

I am going to a watch auction next week and there is an Oysterdate Precision ref 6494 up for sale but I'm struggling to find out much about it including a rough value. The watch is in running condition but looks rather grubby and has a fair amount of patina. Unfortunately I cannot get a look at the movement before the auction so it is a bit of a risk regardless. This is the only picture I have:



Any information would be greatly appreciated! I like the overall look of the watch but don't want to pay too much for it.

Thanks