Replaced 3 of mine earlier today when I took out the fuel tank panels (Thanks KY Grady for the walk through!).
These really should be the standard. My Aux tank up front had some pitting which makes sense as saltwater comes in through those small thru hulls when rocking. If the hatch was secured better, it might not have happened.
For those interested, I attached some pics of what the tanks looked like (dirt/ grime was concentrated by the hatches!), the pitting by the Aux Tank, and after the new hatches were installed. Ignore the filthy deck, just got back from the marina and went right to work.