List Only - is this Centurion Signet worth $100?

is this Centurion Signet worth $100?

http://sacramento.craigslist.org/for/750475379.html all parts are the same, it is probably 15 years old, i don't know anything about it.

I'd offer $30 and buy for $50.
It's probably about 20-25 years old. Bikes 15 years ago had things like indexed shifting (where the bike clicks into gear) and aero brake levers (where the cables don't come out of the top of the brake levers). It's old and doesn't have a lot of the features that would make cycling a lot more enjoyable. A bike this old should be going for around $50 tops. You can find bikes on CL with a lot nicer features for between $100 and $200. I'd keep looking.
Centurion was the predecessor to Diamondback, so it is quite a bit older than 15 years. To answer your question directly, no, the bike is NOT worth $100. I would say $30-50 would be the max.