They're just guides, and often aren't very accurate compared to what counts, which is market value.
You may want to call a local bank or insurance agent and ask them which guide they use for loans and insurance claims. For example in MA NADA is the standard.
The bike's probably worth more than $1200. You've got to research how much they're selling for...check Ebay under "completed listings" at 250's and see what people are paying for them. Check ads, dealers, ect., and you'll get an idea what they're worth.