How to find the NLS_LENGTH_SEMANTICS used for your PL/SQL objects

Use the view DBA_PLSQL_OBJECT_SETTINGS:

SELECT OWNER,NAME,TYPE,NLS_LENGTH_SEMANTICS
FROM DBA_PLSQL_OBJECT_SETTINGS
WHERE OWNER IN ('USER1','USER2');

Join with DBA_OBJECTS for creation time and last ddl time etc:

SELECT POS.OWNER,POS.NAME,POS.TYPE,POS.NLS_LENGTH_SEMANTICS, O.LAST_DDL_TIME,O.CREATED, O.STATUS
FROM DBA_PLSQL_OBJECT_SETTINGS POS JOIN DBA_OBJECTS O
ON (POS.NAME = O.OBJECT_NAME)
AND POS.OWNER = 'SCOTT'
ORDER BY NAME;