It’s usually worth getting a second opinion on anything that expensive, and it’s usually worth waiting for a good engineer if they’re backed up.
I am an engineer, and I’ve seen good engineers and shit engineers. It’s terrible I have to say this, but if you’re buying a house and the owner has an engineer look at a potentially serious problem, you should probably still pay for an engineer to look at it as well. And it’s probably going to be expensive. $450 is a steal.
Also, if you know what you want the engineer to look at, specifically, it will cost less than “getting the house checked.” The former might be a fixed fee, the latter is likely to be hourly and well into 4 figures.