1.
Read this
2. Do you have any chums who play upright? If so, get them to take a ride with you to try out the bass. If it feels and sounds good, make a reasonable offer. Value depends on too many factors that require either good detailed pictures or firsthand sight. And even if it looks perfect it could still sound and/or play like a steaming pile of dung. Kays are generally good workhorse instruments. Many of them have a great big boomy sound, some don't. Many of them have been dropped, fallen off of cars, slid off of walls, etc. Many of them haven't. If the bass is in good condition and doesn't need any major repairs, and doesn't appear to have had any poor work done on it, it could be worth 3-4K easily enough.
Whether or not it's good for the music you'll be playing is entirely subjective. See #2. But bluegrass and rockabilly guys go a$$ over t*ts for them. Some jazz players like them a lot. Any other style of pop music probably has elements of those 2 so it could work fine. If you want to try out for the Philharmonic it's not the best choice.
More useful info:
www.kaybass.com Fretwell