I have a full length one in my 2015 159 that was ordered as a factory option for about $200 MSRP. It is a very hard rubber/plastic material about 3/16 inch thick yet semi-flexible. The top finish is sort of a pebble grain, color black. At time of order I was not sure that I would actually use it as I was planning an insulated plywood floor covered with household vinyl in my DIY camper. After using it outside the van as a pattern for the insulation and plywood I then decided to use it atop the plywood as the finish floor surface in lieu of vinyl. It is super durable and has held up well and still looks new.
Check the Promaster website where it lets you configure a van including options. If not available perhaps it can be ordered through the parts department as if for a 2015. My guess is that the floor of the cargo area is the same.