Silver and 18K 'Gucci Firenze 2921' bangle, made to celebrate Gucci's 90 anniversary, pic from gucci.com
There always seem to be a few 14 karat gold pieces for sale
Gucci have NEVER made 14 Karat pieces.
All Gucci gold is 18 Karat
Some beautiful Gucci silver pieces are described as #silver and 18 Karat gold' This means silver and 18 Karat gold plating (as in the gold parts are covered silver and not solid gold) as the one above.
Most 18 Karat gold jewellery is fairly new (post-1990)
If you are looking at gold vintage jewellery it is much rarer. There are 18K pieces throughout Gucci's history, some even adorning bags, but usually made to order or for special projects such as the range of 18K jewellery designed by Patrizia Gucci (nee Patrizia Reggiani, married to Maurizio Gucci, grandson of Guccio Gucci) and was part of a crocodile themed collection from the 1980s.
Gucci's vintage silver (many with enamel) jewellery (and belts) pieces are very collectible. There were many fakes on the market at the time too. Make sure they are silver, make sure they are Gucci or they are worth approx their weight in silver but no more