I almost kind of want to say that that's a Standard Trailboss. Can you post the side of the seattube? If it is a 'Boss, it'll have the stovepipe, with it having a wider diameter at the bottom than at the top.
that's definately a 250, either a trailboss or a trls250. you can tell by the gusset coming off of the head tube how it goes down on that angle. i have an original trailboss and love it (going on 6 years with that beast)