All of it was open. In fact they now have the Cooper Road open that goes from the back of Cades Cove to Hwy 129 (Deals Gap).
I think it is Parsons Branch that goes directly to 129 from Cades Cove, no?
Cooper Rd I think actually runs to the outside of the "Great Smoky Mountains Park" to, if I recall Happy Valley Rd, which then dumps out onto 129 just east of the Foothills.
Either way, now that it is open, it is a must

Is it still 1 way 'Cades to 129'?
Is it still gravel? Not that it would stop me

I've been on a gravel road or two down there.
I doubt most people even see the Parsons Branch Rd entrance on 129.
As a side note, for those wishing to do the Cades Cove loop, it is closed on Wednesday and Saturday mornings, from May to September, open only for bicycles.
The picture below is the Parsons Branch exit onto 129 (Tenn side). Right in the middle of one of the better hairpins.
129 is highlight in yellow, PB in white. The white highlight is actually off a bit, you can see through the trees that the exit is right in the middle of the turn.