I don't think so. There were hour and minute adjustment buttons next to the time, so I doubt the clock was linked to the radio/head unit in 2015s.Is the 2015 clock above the radio somehow linked to the radio?
Like autoset from NAV?
That's insane. If anything I'd go aftermarket. You can retain basically all the stock features besides USB and even gain some. Check out crutchfield, there are some really cool options.
The original radio has some car settings. For lights and doors. This part will be missing if aftermarket HU installed.