meh, no biggie if he did. if you get home and he’s already got it all apart, just re-time it and put it back together. You’ll know for sure how bad it is / was when you go to start it. If it fires and runs ok, warm it up and then do a compression test & a leak-down test.
I assume that since you are in there you WILL be replacing the water pump as well? No sense in having to pull that back apart in another 10k. Again, OEM components are worth their added cost if you value easy install & want to keep the car for any length of time.