Hi Guy's! I'm currently working on 2 of these GB T-65's. Does anyone know what goes in the area I'm pointing to on the back side of the gallon indicator? Both were packed full of dirt and whatever was there (if anything) has long ago disintegrated. THANKS for your help! Jim

IMG_0936 (480x640) (338x450).jpgIMG_0937 (188x250).jpg