Maybe you have the white stock rim (photo attached) [6 x 15] which was fitted after August 80, but the centre recess is not the same and that recess looks too small for the hub cap version with the tabs removed. (shown below)
View attachment 336064
I believe that prior to that date they fitted split rims 6 or 5.5 x16.
View attachment 336063
But if you search for HJ/BJ60 stock rims - same size - then you may find stock or hub cap rims as more of this model ended up in the scrap yards.