Gilbert lived here and ran his magic studio from his home.
It is believed that this is the same address as 11135 S Irving Ave, as is found in his catalogs. Perhaps the street name changed. The ad below also ran in 1921 Billboard but with the S Irving address and with the name B.L. Gilbert instead of Gilmagico.
Billboard (11/22/1919) for "Gilmagico".
Link: B.L. Gilbert on MagicPedia