Yes, "Guillermo es de Guam" is from a Spanish-speaking country because the phrase is in Spanish and Guam is an unincorporated territory of the United States where both English and Chamorro are official languages.
Guillermo de Lorenzo is 179 cm.
Guillermo de Torre died in 1971.
Guillermo Altair's birth name is Guillermo Altair Ruiz de Huydobro de las Muecas.
Guillermo Wiese de Osma died in 1999.
Guillermo Wiese de Osma was born in 1927.
Guillermo C. de Vega was born in 1931.
Guillermo C. de Vega died in 1975.
Guillermo de Lorenzo was born on May 23, 1948, in Argentina.
Guillermo Raimundo de Vich y de Vallterra died in 1525.
Guillermo Souto's birth name is Guillermo Souto de Celis.
Guillermo de Cun was born on February 10, 1929, in Havana, Cuba.