Ask before the lot comes up. Questions on a listing are public and stay for the next buyer, which is why sellers answer them properly.
The questions
"Can you show every face of the box?" The back and the bottom carry the shelf wear, the crushing and the price sticker. The front tells you nothing. Non-answer: a better photo of the front.
"Can you lay the contents out?" So you can count them rather than trusting the word "complete".
"Is anything a reproduction or a replacement?" Common, often sensible, always to be declared. An undeclared reproduction part makes the whole listing doubtful.
"Can you work the joints?" For anything articulated, loose joints are a real fault and they do not photograph.
"Has it been displayed, and in sunlight?" The polite way to ask about yellowing, which is permanent.
For sealed items: "How long have you had it, and where did it come from?" Treat a seal as a state rather than a certificate.
What protection covers
Missing pieces described as present, undisclosed reproduction parts, damage not shown, or a box crushed because it was posted without an outer carton: seven days from delivery.
Questions people ask
Does yellowing come out?
Treat it as permanent when you decide your number.
Is a crushed box worth bidding on?
At a crushed-box price, if you want the piece.
Can I ask the seller to run a series?
Yes, and in a live room that often works. It is one of the things a show is actually good for.
More: buying toys, what they are worth.