The national anthem has not been traditionally accompanied by musical instruments in formal settings, and there does not seem to be a standard guitar chord sequence used for it. Therefore, an official or commonly utilized arrangement of guitar chords specifically for the song is not readily available.
Here is a simple guitar chord progression and strumming pattern you can try to accompany the song:
Verse and Chorus:
Chord Progression: G Major -C Major -B7 Major -C Major
Strumming Pattern: Down Stroke for two counts with every chord.
Bridge:
Chord Progression: D Minor -E7 Major - C Major
Strumming Pattern: Same as verse and chorus.
You can repeat this chord progression throughout the song to provide harmonic accompaniment. Remember, there's flexibility in musical interpretations, and other chord variations might also align with the melody. Feel free to modify or expand this basic pattern based on your musical knowledge and creativity.