Okay just rewatched the first scene of S05E01 on Netflix, he does do the 52 in the bacon, but 1) we have no sense of how far in the future it is, only that it's in the future, and 2) the date matches the date on his fake ID that he shows the waitress, there is no evidence that it is the same birthday as his real birthday. What there is evidence of is that he buys a big ass gun with no explanation as to why. Clearly he's about to have some kind of a showdown, he could easily die in the final episode of series.
As stated, episodes (roughly) 1-45 were his ages 50-51.
From my point-of-view, I don't think he dies or goes to jail.
It isn't concrete evidence, but it suggests that.
You're right in that the only flash-forward we've seen is him doing his weekly shenanigans.
But I doubt they'd be able to go from 51-52 in the final 8 episodes, however, it is possible.
But VERY unlikely.