The short answer is yes, people will buy them, perhaps with the exception of first year whites.
The thing is its a time vrs payout thing. If you are going to use guru auctions to sell them, fine, go ahead. After all you can leave the pet listed, and let it relist for weeks if you like, as long as you list the price low enough chances are someone will eventually buy it.
If you are planning on standing in a town and selling them then no, don't bother. They are worth so little money and so few people want them that you'd make more money just wandering outside with a party of heros and killing a bunch of stuff
In regards to the low year white pets which you are unlikely to get anything for, try Shing Jea amer 1. Stand in there and spam free pets for a while, someone will take them from you happily and you may even give a new player something they consider a little bit awesome
