Not sure if this helps...ordered our 6cyl 4x4 last spring. It was suppose to be a 2017m/y van, it was built over winter and held in SC for a couple months. It was delivered as a 2016 VIN with the 2017 option packages but with 2016 pricing. Final stages of build happening now at SMBW and pick up is scheduled for 2 weeks from today.
I know that doesn't give you any info on a 'true' 2017 but gives an idea about the lead time. I asked about 2017 when I was there last and was told they had no info. Read on another forum that the window for 2017 m/y vans is extremely small and orders for 2018 m/y starts in a couple months.