RSOLVED-Thermostat stuck?

[mam4.6]

Help a fellow out and confirm my diagnose before I start panicking! Just had some major preventative work done on my X (latter part of June '14, see my thread "preventative time" for a pdf of what was replaced.) Has worked great since, but this evening on the way home from town, I get "coolant temp" message. Bring up Ktemp in the cluster, at 117! Pulled over immediately, turned off the engine, and within 5 minutes, I was down at 100. Turned heat and stratified all the way up, drove home, keeping an eye on Ktemp. Went up to 110 and sat there, would go up if I turned down the heat. Back down if the heat's on. The upper radiator hose is very hot, lower is cold. Heat still blowing hot. No coolant leaks under the X or under the hood, no green in the oil. Level in expansion tank is where it should be. Is my thermostat stuck? Dissapointed if it is, already, after my maintenance, but relieved as well if it's only that. Thot maybe my Indy didn't use an OE thermostat? Will be calling and asking. Have another thermostat ordered, also have a coolant temperature sensor laying in the shop that I haven't installed yet, that will be going in with the new thermostat. Opinions?

Edit: Just checked my pdf, that better have been an OE thermostat for $120!

2nd edit: Idled for 10 minutes with stratified on hot, heat on 90 with fan wide open. Won't go above 103. Turn everything off and to cold, sky high!