The name "Gunwar" (or "Gunvar" - "v" and "w" are intechangeable in Swedish) is strictly a male name, and a very uncommon one (as of today 29 men are named "Gunvar").
"Gunwor" or "Gunvor" is a female name in Sweden. However, very few were called Gunwor/Gunvor before the turn of the century 1900 - in the 1890 census only seven (7) in the whole country (cf. today 18864).
Of the seven in 1890 one (1) was born in 1885; to be exact 15 aug 1885 (the others were born 1822, 1873, 1880, 1889, 1890, 1890 (yes, two in 1890)). Her full name was Gunvor Julia Rosina; she was born in the town parish of Nora, Örebro county as the fifth child of newspaper editor (and former sheriff) Lars Elfving (b. 1840 in Ervalla parish, Örebro county) and his wife Augusta Larsson (b. 1847 in Grythyttan parish, Örebro county).
Gunvor Elfving is issued emigration papers 04 Jul 1907 from Övre Hagge farm/village in Norrbärke parish, Kopparberg county and emigrates 24 Jul 1907 from the port of Göteborg ("Gothenburg"), giving her destination as New York (many people, particularly if unsure of their exact final destination, stated New York although they knew they were going on from there).
So, the only thing that doesn't "fit" is the last name. However, Gunvor may well have married in the US, or she may just have preferred to call herself by another name (Swedes aren't at all attached to their last names, bar noble and old clerical families; changing your family name was and is - still, today - a national pastime).
Searching for Gunvor/Gunwor Elfving in the US may perhaps yield some interesting results.