County free libraries may be constructed, leased, built, rebuilt, furnished, refurnished, or repaired pursuant to the Education Code, or pursuant to this part; provided that, in counties wherein a union high school library district maintaining a district free public library was established prior to June 30, 1912, county free libraries shall be constructed, leased, built, rebuilt, furnished, refurnished or repaired pursuant to Section 27264 of the Education Code until such time as the union high school library district elects to become a part of the county free library system.