If there is a clustered index, that index will specify the order of the rows within a page, and the logical order of pages within the table. Extents will still be allocated and filled as the engine sees fit, and there is no way to determine the order in which the rows were inserted into the table because the clustered index will override the order of the insert operations.
The concept of "order" of rows or columns within a relational table is meaningless. Result sets certainly have order for both rows and columns, but tables and views have no order in a truly relational database. Whatever order the database engine imposes is an artifact of the storage engine, that order isn't "built in" logically and the database engine can change them as it sees fit.