The only difference between the 39 take down and the 59XX is the 39 has a removeable barrel bushing. He will see how it removes once he pulls the slide and removes the recoil spring and guide rod, which removes identical to the 59XX. Other than that the take down is identical to the 2nd and 3rd gen S&Ws.
For over 27 yrs I carried everyday as issued 39, 469, 459, 6904, 5904, 6904, 645, and 457. I've run many thousands of rds thru them, used them hard, and they've saved my bacon on more than one occasion. Other than the bushing they all field strip the same way.