I can at very least see an elbow heater installed, as far as tank heaters go I would attempt to confirm that. Some people believe that because they have a "heated or enclosed underbelly" they don't need to heat the tanks. Depending on climate or furnace usage (manufacturer's idea of heated is usually a vent pipe "leaking" in the enclosed area and is only good if furnace is running) this may or may not be true, it varries between make and model. Living in MT I would not depend on the enclosed or "heated" underbelly...I'd freeze up in a heartbeat! So again, I would confirm the tank heaters, but it looks like at least an elbow heater to protect what is outside. Also be careful of your battery usage with the heaters on...it can drain things pretty quickly if you're not paying attention. Look at http://www.ultraheat.com
to determine the amperage of each of the heaters so you might be able to predict the usage. They also tell how to test them once installed, so that could be a good way to make sure it's the right switch, and make sure they work.
As others stated the two pipes are your low point drains for winterizing, and they are sticking out quite a bit, so I would be wary of those freezing as well. A solution would be to at least shorten them up to just below the spray foam so they're less exposed.
I'm currently working on some winter fixes for my TT and will post soon, and let everyone know how it works come hunting season. Hopefully I won't have to learn the hard way what I may have missed!
P.S. Don't run the tank heaters without water in the tanks!