I checked the refurb section on Apple and for this one, it is still $400 more. The $1300 is out the door, as we have no tax due to being military. I'm assuming it is the i5, although I only got this info from calling..still need to head there to check it out more.
I'd say there's a 99% chance it's i5. The i7's in iMac's are BTO and they don't put those on display. I checked the 3rd party certified refurb sellers and they have the 2015 model with this config around $1550 with Apple 1 year warranty so it seems to still be a good deal. I'd check if it's 2015 or 2017 just so you know in the future but after looking around some it probably doesn't make much difference in the end.
No being an actual Apple retail store, I'd open a doc up and hit every button on the keyboard at least once, I'd go in settings and test each button and gesture of the mouse, and look for physical damage and then if all is good, check out with it (try to get a box for everything as well).
EDIT: My previous post about them wiping the OS, in this case, is probably not true. I would doubt that they are going to take it into a backroom and reinstall the OS for you. That's not necessarily bad, as you can easily do it yourself if there's unwanted junk on there from people playing around.
