I'm of the opinion that the Jefferson is oriented correctly in the NGC Slab as presented by the OP. IN should be at about the 7:00 position with Jefferson's Profile in a vertical position. This does look a little awkward in that the tendency is to rotate the portrait about 5 degrees CW so that the base of the bust looks level. If you've spent anytime loading these into DANSCO's, you quickly find out that the Reverse should be used to orient the coin in the holder as there is no mistaking level when it comes to the base of Monticello.
I wanted to make one more quick comment to thank jloring for posting something useful. It does work, and apparently with the new slabs. The only down side is that the photo of mine on the website is still slanted the way they originally did it. This is much better, and it looks like it's supposed to. If the coin obverse was supposed to look slanted it would appear that way on the US Mint website and 99% of the other places that show it. It may be a degree or two off still, but looks a million times better, and the mint mark is perfectly straight.