Ya, I think it was a hoax.
If you take a very good look at the pictures of the burns on his skin and the burns on the shirt, they just don't match. The size, the spacing, and the number of dots, especially the bottom row, just don't work. And the shirt would have had to be at a very unnatural position on his body - they are high up on his shirt, right below the neckline, but on his body start under the ribcage.
And the icing on the cake for me was considering the angle that he said the grating was at, and trying to work out the funky angle he would have had to hold is body in to make everything line up - he essentially would have had to be limboing under the craft to make it work in my mind.
Which bummed me out because I liked this case.