Stock exhaust manifolds

if it still moves its pretty obvious how it comes apart once the manifold is off. if its froze up it shuld be open and will probably not really cause a problem.
I have seen them pluged in various ways. Ive seen little expanshon plugs, like a mini freze plug. Ive seen them drilled and tpped for machene screws (5/16 i think) , others for small pipe plugs. ive even seen the holes welded shut.