I've got a doubt here. Do I play G flat or G natural?? The accidental doesn't come in till the 3rd beat while the key signature does not have G flat, while the lyric has an accidental but at the second quaver beat, so that means even if the lyric counts for the instrument part, the note still stays with a G flat, while the chord above says it's a G Flat chord. Here's a photo:
For starters, it's no G♭ chord. As it states, it's D♭m7, with a G♭ bass note.
Which means, assuming you're asking about the G in the bass clef (note on beat 2), it must be G♭, which means it's a typo.
EDIT: just checked another sheet music, and the D♭m7 is beat 1, then beat 2 is G♭9. so it would appear - a. it's not a slash chord. b. the second chord is G♭9, and the bass note is in fact G♭. A simple (common) ii>V>I just in that bar.