You might try a search using the term "rear axle snubber".
You probably won't find anything specifically for your truck so look for something that fits- lots of different vehicles used the same style, especially Jeeps. Measure the mounting holes figure out the height you need. You may have to do a quick comparison measure on some different vehicles. Energy Suspension & Prothane have universal fit items, but they may not fit without modification.
For a starting point look at a '87-'01 Jeep Cherokee, I think the bolt spacing is correct & there are different heights. CJs & Wranglers used the same style but I can't confirm the bolt centers.
BTW please put the vehicle you are asking about in your signature- you say it's a "first gen", but a first gen what? I can tell it's a Trooper from the picture, but maybe not everyone can.