That is typical wear and marks fairly easy there. You may also see a grey spot where the trigger stop hits inside the frame.
The R8/TRR8 327s are excellent choices but takes quite a beating because of the black coat finish. My R8 is all scratched up.
If they are selling new at a LGS, and not used i wouldn't worry bout it. Besides, you dont see that wear when you close the cylinder. And when you do get it, clean it. Because it has been test fired .
Welcome to the FORUM! Make sure you share photos of it when it becomes yours! I bought my 1st 7 shot in March. 686-6, 5" Pro-Series. Sure a pleasure to shoot. Bob