Ace thermostat question

[pjbowman]

My Ace has always run cool, so I assume the thermostat is stuck open. Since I have my radiator out now, going to check the thermostat also. See the attached (I hope) picture, does this look like the correct thermostat? How do I remove it to check it? I don't want to just start prying on it and damage anything, so looking for advice!