It depends on the context. If Guatemalans are talking about their country, we usually say "Guate". If you're talking about Guatemala as an airport destination, it's "GUA". And on the websites, it's "gt".
GDL is the abbreviation for Guadalajara, its on all the souvenir shirts in the airports and in San Juan de Dios
It is the abbreviation for the state of Jalisco (capital: Guadalajara), home of mariachi music, tequila and jarabe tapatio.
Guadalajara itself (it is a city).
Guadalajara Metropolitan Area's population is 4,298,715.
Guadalajara is by itself, a city.
Guadalajara is farther north.
CB Guadalajara was created in 1972.
Guadalajara - film - was created in 1943.
Guadalajara Cartel was created in 1980.
Guadalajara Macrobus was created in 2009.
Guadalajara Orchestra was created in 1915.
The population of Province of Guadalajara is 251,563.
Nacional de Guadalajara was created in 1916.