The best reference I know of for the grey 38's is the above natural colour photo by Don Martin published in 1947.
Here is black and white picture of an in service train published in 1947
Here is a NSW Archives black and white picture of 3801 in service with train at Stanmore dated 1946
Finally the following black and white print shows how difficult and deceiving black and white is. Both 38,s are grey, as is the bridge, yet the greys on the photograph vary due to where the sunlight falls.