^Yes. Also, if you're familiar with what the styles look like in person then you can pretty much tell in pictures.
Another way is if a seller has multiple auctions for multiple sizes...that's always a red flag.
As for comfort, I think they're pretty comfortable. I have a pair of the flip flops with the charms from a couple of summers ago and I like them. The flats and wedges are ok (I've tried some on), though you may need to add in a Dr. Scholls or Foot Petals cushion to some of them.