My husband did a motor swap putting on 04 300m motor in a 99 LHS. On the test drive a valve got hung up on these. Not sure where they came from or how they got in there. Do they look familiar to anyone? Thanks for your help.

 

Those are pieces from the bottom of the plenum/upper intake manifold.
The SRV (short runner valve) or a set of butterflys in the manifold "tune" long runner/short runner at various RPM ranges. That piece camd from the gasket area. There are a number of them that the tip of act as a bearing thet the rod pivots on.