It appears to be a regular Colnago Super. 'Oro' would be gold plated, and it's got none. There is a dent in the right hand chainstay (for chain clearance), which means it's not a Mexico (the México has completely round stays, no dent). See photos of Colnago Super and Oro.
Current market value, around £6-800. Although the market, even for Colnago bikes is quite depressed at the moment. If you wanted to sell it here, probably £5-600 would be more realistic.