Fuel tank - is this normal?

[Solar]

I have 1967 Wanderer and i am currently trying to get it back purring/growling on the French roads. It's under going repairs and servicing with the roof and engine, but on checking the fuel tank, as i want to empty the old fuel, i noticed this bolt (see photo). It was under a clump of epoxy/silicon, it has obviously been leaking at some point as someones has tried to patch it up. Is this bolt the drainage bolt? or is it some bodged repair? My manual just states emptying the fuel by disconnecting the fuel pipe from the union at the tank.

I know the van was bad with its mpg but maybe this was part of the problem, haha!

 

[JJ Autosleeper]

Bodge. No drain holes in the original tank on mine. You just take the filler pipe or fee union apart to empty it.
I had a new ally tank from Tim Commer. Highly recommended. No idea if he send tanks to France.