There was a change in the tanks depending on your seral number. This company has both your left and right side tanks in stock for both serial number changes. Hustler Mower Parts and their diagram will give you the correct part number.
A google search of the part number will turn up other vendors that may be cheaper.
If something (like alcohol gas) is eating holes in your fuel tank, you can be sure that other holes will appear after your repair, but your holes are so perfectly round. Is someone armed with an cordless drill and Swiss cheesing your tank?