Yes, they are definitely listing duplicates. I checked one of their dupliate listings and it is identical in every way (to my eyes.)

What eBay says, though, is that it's at eBay's discretion about whether to remove duplicates; based largely on the sales of each duplicate listing. If they're doing well, eBay will let them slide. If they are basically not selling, eBay can either remove the listings, suspend the seller or just lower the listing's place in the search results.

I guess there's no harm in reporting them for duplicates - which is what they are - but eBay's action may depend on a few things.