Ashamed to say, I have not read The Watchmen yet

I've purchased at least 7 or 8 trade paperbacks from Amazon (or gotten them as gifts) and all have arrived in really good condition. They do sometimes put a UPC sticker over the original UPC printed on the cover. This would probably only bother a serious collector. Considering you will not be buying a 1st print it's not a big deal. I would be a little more suspect of auction sites like eBay. Comic book sellers will sometimes lie about the condition of the books they sell. And you are unlikely to get much of price break going the auction route (there's a good chance you'd pay more on eBay). If you're really anal, you can probably pick this up at your local Barnes & Noble (or have them order it for you) which would allow you check the condition before you buy.