Do the people on the thread you posted believe that the military will install Donald Trump as president, and that military tribunals will be held to prosecute the coup plotters?
So, inherent in your question is the notion or possibility that the military is in control and able to do that? Ergo, the Insurrection Act (one or more of its incantations, 1807/2018/etc) is/are currently in force?
If yes, then yes.