Which G/L list are you taking about? Materials are not directly assigned to any G/L. They are assigned to a valuation class in the master which is assigned to G/L accounts in OBYC.
If you are looking for the valuation of the material in the stock account, you can use MM60. But this does not show any G/L account.
To see the stock accounts, ask your ABAPer to write code joining MBEW-BkLAS with table T030.