It's a '95 AMP B3, the same as mine, the Risse is the Astro 5, a good shock, shame about the frame cracks, but not a bad deal if you've go it for free.
Is that an aluminium frame? If so, do you know the aluminium alloy used in the frame and the heat treatment used? That's very important when welding aluminium alloys that are going to be stressed.