Is $1200 a fair price for a CLP860 clavinova that is about 8 years old. Or is this too much?

This piano might be 8 years old. But it was introduced by Yamaha in 1998. So the "model" is 12 years old.

$1200 is high, I think.

You can get a better, brand new YDP160 for just a tad more money.
Better as in:
- 3 level sampling, instead of 1
- new, instead of 8-12 years old, worn

You have to look at what else the same money would buy.

I bought a P155 with matching stand for a little less. The P155, I think has better specs all around except for the size of the speakers and amp and comes with a three year warranty.