He also doesn't look that skinny to me. My 2010 spider male was a late 2010 and he's sitting at close to 1000g right now and looks like that. He takes all the food I give him and turns it into length over girth.
That is just like our adult male spider too (2009/early 2010ish). He eats and eats and eats and just stays long and lanky. It is almost comical to look at him because he is so scrawny.