You're saving about $200 off buying them new, so if you wanted them, it's not a bad deal. Brand new from Yamaha's site, they would be about $1600, not counting any shipping charges.
That being said, I bought the side cases when I first got the bike, but I never really liked them. I didn't like that they had to be opened with a key, and I didn't have a ton of confidence in the longevity of the locking mechanism. I have Pelican type knockoffs on my bike now which I much prefer. Were I in your shoes, I'd probably be shopping around for something else. Happy Trail makes a rack system and pretty durable aluminum panniers, though they aren't as flashy as something like a Jesse case. The big advantage of the Yamaha panniers is that they hug the sides of the bike better than a lot of the aftermarket systems that use bolt on racks, since the Yamaha panniers use unique attachment system that doesn't require an actual rack. Which means they can be removed from the bike without leaving a lot of hardware behind.
The knockoffs I use have been on two different bikes now for a total of around 55,000 miles, still going strong. I've tried two different styles of top loading metal panniers, and found that I prefer the side opening suitcase style boxes. Just a personal preference.
The photo is what I have on my bike. That's my touring setup; normally the top case is a lot smaller. The cases came from MCM Electronics; I bought them years ago, but I think the big cases were around $50 bucks each. They cost a little more now.