400 seems OK for the year. but personally, I'd pass on it.
With boats, there are people who buy them, and then never use them. I see older boats all the time with less than 100 hours on them. Heck... I came across a 99 Yamaha that only had 18 hrs. Probably was used a couple times when they first bought it... and it sat in a garage. (looked new)
Look around, you will find a low hour boat.