There was never good reason to believe that date. The rumour (of that date, not of LTC being added to Mt.Gox) was based on fabricated evidence.
Are you implying that there is real evidence that Mt.Gox are interested in handling LiteCoin?
Yes.
https://twitter.com/MagicalTux/status/320355219189948416
"@MagicalTux a lot of ppl speculating about Litecoin and Mt. Gox. What's the truth?"
@MagicalTux "@onecrazychief support will be added eventually, an announce with more details will be posted next week"
Also...
https://www.facebook.com/MtGox/posts/455515957866150
...and there's an actual Mt.Gox ticker for LTC and NMC, which keep being updated.
There's more evidence too but you get the picture. This doesn't mean for sure it will actually happen, but it's beyond reasonable doubt at this point that Mt.Gox are interested in handling LiteCoin.