The casual sellers who have a puppet to sell, they may not know much about it, so they take a photo or two and sell. These sellers often have no idea what they are selling and are honestly selling their item to the best of their ability. For these puppets, you should always ask extra questions, more images if necessary. If in doubt, leave it out.
Then there are the dealers who are registered sellers, their address and business details are visible. These dealers may not have specific knowledge of puppets but will usually answer questions and will try to hold on to their seller score. I don't know of any dealers who are trying to deceive in their listings.
Then we have the repetitive sellers. They buy from ebay, auction or privately to sell, so are actually dealers but don't disclose this. One seller in particular, buys poor condition puppets from ebay itself or auction, then gets to work making them look like new! The seller repaints the noses, parts of the face, bamboo limbs etc. New sheepskin fur will be used and costumes changed and new items added. There is no mention of these new additions or restoration work in the descriptions, in fact, they often lie in their descriptions.
The seller who bought and sold the puppet below, with a month between, is the most prolific seller of Pelham Puppets on ebay who restores entire puppets, often the puppets were very different when sold at the original auction.
There are a couple of other sellers on ebay who do a similar thing, they have several ebay i'd's and use that to their advantage.
I think a buyer should be told if the item has been altered specifically for the sale.
Obviously we don't always know the full history of our puppets, but we learn to tell what has been done to them, if anything.
The facebook groups are a good source of friendly chatter about your hobby.