Sounds like an Early Guarder/LCT body to me,back when they were made of Duralumin instead of steel.
Anyhoo,obvious grip suggestion(LCT),but bluddy 'spensive:
http://www.wgcshop.com/wgc2008/main/product_detail1.php?item=LCT-PK-57
'Nother one by 'GR'
http://www.ebay.com/itm/AK-Real-Wood-Vertical-Grip-for-Airsoft-AK-AEG-series-/200954515455?pt=UK_SportingGoods_OtherSports&hash=item2ec9d28fff
Not much luck in the used side,mostly tactical style or black pistol grips. No bakelite effect either,I hear some painting work has to be done to it. The BO AKM13 has an actual bakelite pistol grip IIRC.