Can half cooked pork chops be cooled then fully cooked later?
Even though you turned the oven off when you left, there was still likely enough residual heat to continue cooking the chops.  Rather than a half-cooked chop that sat out for 4 hours, you've got mostly or fully-cooked chops that sat in a warm environment for 2-3 hours.  Whether they hit the recommended internal temperature (which is now actually 145F with a 3-minute rest for fresh pork, rather than the 165F quoted in other answers, at least according to the USDA) is anyone's guess.
From a culinary standpoint, since they've been pretty well cooked, baking them back up to that temperature (or more likely to 165F, which is the recommended temp for leftovers) will probably dry them into leathery little pucks.  If you're going to risk re-cooking and eating these, I'd recommend a higher-moisture cooking method like braising; chops stand up pretty well to this treatment.
As mentioned in comments, these have been sitting at near-room temperature for longer than is generally considered safe.  And without knowing what temperature the interior of the chops reached, it's unknown how safe they would have been even if you returned before they cooled into the dreaded &quot;danger zone&quot;.  There are a lot of questions here from a safety standpoint.  I'll quote another answer here, as I think this says it best:

The safe limit for raw or cooked food is 2 hours in the danger zone (40-140° F or 4.4-60° C).
If you're a restaurant owner or cook, you must follow this rule [...] If you are not working in a professional capacity then you are not legally required to follow it, but if you are serving guests then it would be irresponsible (and possibly actionable, if someone gets sick) to do otherwise.
If you're an individual serving only yourself, then take whatever liberties and break whatever rules you want; it's your food, and your body.

I personally would probably write these off as a loss, but I tend to be fairly risk-averse.