The problem with checking versions in a PM is that you can run into this, where the sender prints the label (which could have prepaid postage on it) right away and it is not fair to present them with additional requirements on the swap after they have accepted it. You need to use Requester Conditions if you are looking for specific editions/covers because their books are posted correctly and swappable as long as the ISBN/title/author/book Type match.

You have no choice but to mark the book received without a problem unless I am misunderstanding and you actually had used a Requester Condition statement that they accepted even though their book did not meet it.  You cannot mark a book a problem swap - not meeting Requester Conditions if you did not use and RC, but send just additional conditions in a PM. That isn't really what that option is for and it isn't fair to the sender. The proper use an RC would have allowed them to deny your RC and get to the next requester instead of cancelling a request and having the cancel on their account and losing their place in the FIFO line because of something done outside of the requesting system.  You can read how to set up Requester Conditions in the Help Center by searching for "requester condition" under Browse Help Docs.

Even if he canceled from his end before he accepted it, he would have lost his place in the FIFO line.  That would not have been fair to him.  Re-post the book and put in an RC.  Hopefully, no more problems. 

Todd--Melanie is right, using an RC would have been the way to go, but regarding your request--are you sure that the original person who you requested the book from is the one who did indeed send it?  Since it went the full five days, the request might have rolled over to a new sender who sent the book out almost immediately.  If that's the case you may still have a chance of getting the edition that you want.

Todd, You can set up A RC to cover the situations when the cover art matters to you, then if you are requesting books when it is not an issue, there is an option tio mark a box which effectively says "do no apply RC to this request", and that request goes through without an RC connected to it.

You can't have the same edition on both your bookshelf and your WL at the same time. So you may want to wish for the book and then not post yours until your wish is fulfilled.  If you put the book on your WL before you post it then when you post the book it'll be offered to you.  If you post the book first then it won't let you wish for the book  since there is a copy in the system.  I'm not sure declining your RCs would eliminate this problem. 

You might not want to go by the cover art as listed on PBS as sometimes that will change.  Anyone can submit a new cover graphic, and if it is WLed, that has plenty of opportunity time-wise to change between when you add it and when it is offered to you.

Not that many around here are sneaky, but someone could take advantage of you and say "Sure, it matches." sends their book to you, and submits a cover graphic that matches their book.  

Giving a short description of the cover in the RC would probably be the best way to go.

Maybe it would be easier if you found out the exact publisher and year for the edition you wanted rather than rely on the cover art. Do stay away from long, detailed RCs in any case. Many people don't even read them they just decline.