Yes you SHOULDbe able to buy it back unless they feel like being hard asses. I work at a body shop and when my 03 2500 hd was totaled they asked me if I was intested in keeping it since they knew I worked on them for a living. The truck was about 7years old with 72,xxx miles on it and I payed (they deducted off the settlement) $1500 to keep it. I put $200 in it to make it drivable and drove it till just a few months ago that way at which point I fixed it properly lol.
So if you really wanna keep it, then when the call you up and tell you it's totaled let them know that you are interested in keeping it and they should give you a price after which you can decide if it's worth what they want.
To Freak be carefull what you do and tell people because once they appraise the vehicle if you take anything off it then they can nail you for insurance fraud. If you wanna take stuff off then it needs to be done before the appraiser looks at it.