[DavidG]

You're right, it's not original if is missing the end triangles. It is a bit odd to have those openings on a new tank although they may come in handy in the future. It is a major league minus that it does not a have a drain in the bottom as you would not want to store it over the winter, for example, with fuel in the tank. You can still siphon it out, but you won't be able to remove all of the fuel. Perhaps a better strategy for a couple of months' downtime would be to keep it ful to minimize the amount of air (oxygen) to slow down the breaking down of the fuel.