After bonding two glass faces and allowing the joint to fully cure, can you continue grinding and polishing the bonded pieces along with the epoxy seam/joint? Will the seam polish?

You can still grind and polish the joint with very little visibility. The larger the layer of glue the more visible it would be though. Hxtal is more of a plastic so it doesnt polish the same as glass. If you were to go a gap fill then work the surface it would be very visible. But with the laminated joint its such a tiny line its barely visible.