Got the rocket launcher schematics, but there is no option at the workbench to build it?

Are you sure you were at a Workbench and not a re-loading bench? Also, it's called the Rock-It Launcher, so look for that.

Yep I was at a work bench. It was nowhere on the list:(

were did u get a rocket lanucher schematics ??!!

Nellis AF base in one of the big hangers sitting on a shelf.

Repair skill?