shareoptions is not involved here ...
when using the INDATASET/OUTDATSET clauses IDCAMS allocates with <DISP OLD>
if You have the dataset allocated and You do not have <integrity> issues then
allocate the datasets using the jcl DD statements and use the INDD/OUTDD clauses
When I tell somebody to RTFM or STFW I usually have the page open in another tab/window of my browser,
so that I am sure that the information requested can be reached with a very small effort