If you're talking about the two current offerings available in the 2012 catalog this is what they look like;
Colt's GCT (Gold Cup Trophy) - High rise beavertail, Combat Hammer (Modern look)
Colt's GCNM (Gold Cup National Match) - Duck bill safety tang, Spur Hammer (GI look)
If you're talking about older Gold Cups here's a visual. (There are a number of Gold Cup and National Match pistols manufactured from 1919 to present. Far more than I have space to list.)
Top to bottom: 1960's GCNM, Series 70 GCNM, Series 80 GCNM and a GCT.