While driving home from WV to MS by way of KY, I took a detour off I-64 to clinch the Mountain Pkwy (at least for now due to a reroute under construction). At the junction of US 460 and KY 114 east of Salyersville, I saw this new looking sign showing that the Mountain Pkwy has been extended east from its eastern terminus along US 460 and KY 114 towards Prestonsburg. Since I had driven US 460 from Paintsville to get to the parkway, I didn't have time to detour east on KY 114 to confirm any additional signage.
The reroute section under construction is west of Exit 57 around the KY 134 junction and is now visible on aerial photos. There's a lot of work left to go on the east end of the reroute section.