Sure curiousity is permitted. Thats why I was curious what brought up the question. Typically no one thinks about simulators (Thunderflash, Arty Sim) until there has been some sort of incident. If you searched on Google you probably found B-GL-385 Grenades and Pyros from 1976, however it was amended in 1991.
If you have DWAN access and can find the epub library there is an ammo version of the pub. By searching the epub library for C-74-370 you will find it, but it doesn't have any more information than the B-GL.
Not a big fan of the thunderflash, it is a poor representation of the item it is suppose to simulate.