http://www.geheugenvannederland.nl/?/en/collecties/decoraties_maastrichts_aardewerk,_1836-1969/petrus_regout,_een_beladen_naam

Could not get the link on this site but the above will give some history of the family !! As to what your item is I can not see enough to tell what its use might be Need a clear pic of the entire piece from the front and another looking slightly down into the top !!
When you see a stamp added to an original factory mark it is usually an importers stamp !! . KGP was more than likely the import company !!