The sight glass on a Bowser 575 is not centered in the opening at the top of the door. There is a metal bezel that has the opening offset toward the top. A glass goes in between that is lettered "Glass must be full..." so there needs to be space for that lettering below the sight glass opening.
See pic below.
Here's a link to a repro sightglass opening bezel.
https://www.gaspumpheaven.com/product/bowser-575-sightglass-bezel/Here's a link to a replacement sightglass outer window that shows the lettering.
https://www.gaspumpheaven.com/product/bowser-575-sightglass-window/
