I don't see any reason why they will need to give Wolverine his adamantium claws back in DOFP. As surprising as this sounds, it's his mind they want, not his body...
The whole concept is sending present day Wolverine's mind back to 1973 Wolverine's body, and guess what, that Wolverine still has his adamantium claws!
It will actually be cool to see Wolverine "wake up" after his mind has been sent back and when he pops his claws he can look at them possibly with longing. The idea to show how he has missed having the adamantium claws...
A simple smile could be used to show this, right before he starts taking care of business...
But anyway, the point is that for this movie there is absolutely no reason to give him back his adamantium claws. If they do it it will just be to get the audience to go "yay"!, but will serve no purpose. That would be better served in a future movie.
To me, this movie should have effectively 4 different Wolverines. Hear me out on this...
First you have present day Wolverine. This is the one that is approached by Magneto and Xavier at the air port. Has anyone figured out when this would be in relation to X3?
Next we know we will have the 1973 Wolverine to which the present day Wolvie's mind will be sent. So, what is 1973 Wolverine doing when his mind is swapped out? Is he in Vietnam?
Then we would have a future Wolverine, the one that famously fights a Sentinal in the comics with Kate Pride. But this would be a different Wolverine than the one in the airport (same one, but older). Again, the Trask timeline has the Sentinal Mark 5 released in 2020. This version will likely be the one that takes control of the nation and causes the concentration camps, etc. To me, that scene where an elder Wolverine, wearing the brown leather jacket, takes down a Sentinal is such a visually pleasing scene that they have to have it in the movie.
The fourth would possibly be a brand new present Wolverine after the past is "fixed". This could possibly be an Age of Apocalypse Wolverine...
The different timelines thing can really cause issues for the general audience, depending on how the story is shown. They may try to go simple, which would be Sentinal have taken over, send Wolvie's mind back to 1973, change the past, change the future. So what I mean is not really explain and/or show the GA that these are different realities, which means different Wolverines...
The one place where I'm confused is why start this 3 years after The Wolverine? If this is all based on a dystopian future that hasn't happened yet, then why not start us in 2025 after the Sentinals have taken over? The reason why I feel that the present Wolverine is not from the time where things are really bad (yet) is that if they were Wolverine would not be traveling on a airplane and nothing was shown in The Wolverine to make us think that these robots are going around controlling things...
So this begs a question...
Is the story they are going with simply that they need to change something that did happen in the past to prevent the dystopian future (which has not yet happened, but will in like 10 years), or do they need to prevent something that was changed in the past that created a different dystopian future. I know, confusing, right.
Think about it this way...
616 reality = Normal timeline that does not have sentinals. Is this the one with Wolvie, Xavier and Eirk at the airport?
811 reality = Days of Future past timeline, after something in the past was changed. Are they using this timeline at all, or just using the 616 and saying that normal events would have led to a dystopian future?
295 reality = Age of Apocalypse. Will they end the movie with this being the "fixed" future timeline?
So will they go with different realities, or just one timeline (reality) where stuff changes around the character?