RX7Club.com - Mazda RX7 Forum - diagnosing overheated rebuilt 13B-RE

Well, first off, here's the car:
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/status-my-friends-black-91-fc-ported-cosmo-13b-re-533896/
I'm looking for responses from knowledgeable people, as opposed to opinions or random guesses.
Anyway, there is roughly 2,000 miles on the 13B-RE since I rebuilt it. Keep in mind that I used the Rotary Aviation Teflon encapsulated combustion o-rings as opposed to the stock ones.
This is what happened and it's definitely NOT something that I would have done, but it happened during my absence:
Apparently, a few weeks ago, my friend mentioned that something was slightly leaking and it was getting on the top of the plastic under-tray. He asked me what it could be, but since I wasn't there, I shrugged it off and said it was probably the oil cooler because it's been dripping slightly over time and onto the lower plastic under-tray. He mentioned it felt slippery. I just told him to check his oil routinely, and it's always been fine. I wasn't alarmed because the 2nd gen oil coolers tend to leak near the lower fitting. It was leaking in that area anyway. Well, it turns out that it wasn't oil, but rather coolant. It apparently got worse and eventually all the coolant was lost because the way he mounted his Koyo radiator, it was up against the bottom of the oil cooler and the oil cooler eventually wore away a small hole in the radiator. The leak was right near the oil cooler fittings. Also, when he originally put in the new rad., he didn't bother to put in the low coolant sensor because he hated the beeping soo much. This is how he ran out of coolant without knowing it. Well, I came over about 3 hours ago because he called me and said his car was having trouble starting. So, during my quick check of everything, I noticed the lack of coolant. So, 2 gallons of water later, it was full. So, noticing that it was leaking from somewhere, I took off the plastic under-tray and after pushing the radiator slightly away from where it was touching the oil cooler, I noticed that it had worn a pin-hole in the radiator and all the coolant was trickling out rather quickly. Long story short, apparently it had been run without coolant for atleast 100 miles and he said that the oil temp's stayed the same and the coolant temp gauge got slightly hotter and stayed that way. After I found this out, I called it a night. I mean, I only ported, built, and installed the engine for him. No biggie, right? lol. Also, when I showed up, the car started as usual for me.
So, here's my question(s):
Any tests I can do to find out if the overheating caused the irons to warp?
All I can think of doing isdoing a cold compression test, and then another one after it gets hot. Then I'll stop the radiator leak and fill it with water and check for o-ring failure (bubbles in the coolant, etc.). Other than that, what other tests can I do to find out if the block is warped from the overheating? This is basically my only concern with the car right now. I need to know what has to happen now with the engine. Either it comes out or it stays. If anything is warped, that means another 13B-RE longblock has to be bought and rebuilt (by me), and trust me, I do NOT feel like building him another RE already.