Maybe I shld try sweeping (.. a new word I've learnt) the coin into another account to see if it's legit.... but is that like trying the key I found in a front door even though I know full well it's not my house?
Sweeping is like replacing the lock for your own lock. It also puts the burden of securing the funds on you: your computer should be free of malware, and you shouldn't lose access to the new address. And like I said: you should probably not trust the website that was used to create this paper wallet anymore, so you can't just make a similar paper wallet (there's more to it than going to a website and clicking print).