SVRy coaches

There was a thread a short time ago on Sumpter Valley coaches and their origin. I saw a picture last weekend that should muddy the water a little more. Everything I've seen pictures of in the past as far as our coaches started at #20 and went up numerically. The picture I saw at the Oregon Trail Museum in Baker City showed Mail-Express-Baggage car #1 and Coach #1. The picture caption read around 1900. My guess is a bit earlier. Coach #1 was similar to 20 in appearance and had the small cylindrical object horizontally next to the stove chimney which I presume was the expansion tank for a Baker heater. The picture appeared to be taken in the Boulder Gorge area.
Incidently, I was reading through the 1916 valuation report and it shows at that time a coach and a car body being used as bunkhouses at Thompson. I wonder which one?