First read Note 193554 - Stock/valuation data of previous periods as for over tenyears some of those fields are not updated in current value tables MBEW (also MARC) Then take a look at history tables MBEWH (also MARCH) and at FM MBEW_EXTEND documentation.
(Ref: Note 415349 - Usage of modules XXXX_EXTEND for previous period values)
For curernt/previous period use table MARV (per company code)
Only if problem not yet solved, check in which Valuation Area (plant or company depending on Customizing) were the movement executed.
Regards,
Raymond