Fully agree with your assessment. Appears to be some pitting on the rear of the bolt as well. Carbon blowback on the stock base plate and some impact marks on the shell deflector. No pictures of the bolt face or rollers so it makes it difficult to make a definitive opinion. I'd bet my first born the rifle is fired. No disparaging the seller, but I've had dozens of these things, and still have about a half dozen, and my opinion is that rifle has been fired.