One heater hose runs from the top of the thermostat housing back to the firewall. The other heater hose will be the smaller diameter hose coming from the top right side of the water pump. Both hoses will run to the firewall where they connect to fittings that connect to the heater core.
I personally have never heard of heater hoses being reversed but I guess it's possible. It may be more likely that the heater core is plugged up. Remove the heater hoses from the thermostat and the water pump and use a water hose in one heater hose to flush the heater core out. Direct the other heater hose into a 5 gallon bucket. When you flush the heater core a lot of crud will come out the other hose. Flush in one direction until it runs clear out of the other hose then reverse hoses and flush in the opposite direction till it runs clear. Connect the hoses back and top off the antifreeze and the heat should work much better.
The clogged heater core is a pretty common problem on Dakota's.