Obviously they haven't gotten it off the ground yet if Scott doesn't know about it. Unless they changed their minds about it. Maybe Scott's gotten burnt out of television? I remember him saying that QL was fun but very hard work because he was in basically every scene.
They didn't say "Sam's in the 50s", they said "Sam's in his 50s" - the reference is to his age, not the decade he's living in.
In TV there's many a slip twixt the cup and the lip and the studio and the producers would have a lot of stuff to work out before they got to the point of casting the thing so I'd say Bakula's comments tell us absolutely nothing about whether there might be such a project in the offing or who far along in the long development process it might be - except to indicate that they haven't reached the point of negotiating with him yet, assuming having Sam appear in the pilot is still the plan.
If I recall before the screen went blank in the final epsiode, he was in 1969. April 2 or 3, 1969. He leaped into the same time Al "leaped" out in the episode M.I.A. from the Season 2 finale.