Don't know if you will find OEM Yamaha bags that cheap, even used. You could check out VIKINGBAGS.COM They have some Yamaha Specific bags for the 1300. You might find something that is interesting to you.
I dont use their saddlebags but I do have one of their large soft bags that fits on the sissybar and luggage rack. I used it on a 7000 mile trip last year and worked well. I would think that if the saddle bags specifically said for a 1300 that you wouldn't have a problem. Maybe a call or computer chat with someone there would be helpful. Good Luck