I ve gotten myself the same bongo . (almost ,
Its being kept for me i ve made a down payment )And collect it in november after my holiday !
It looks exactly the same as this one . The shopkeeper says its 5/6 years old .
It dous not have the raul mark . But other than that its exactly the same as this one . 
Same wood same dimensions same hardware.The same stamp on the heads.
Anyone can sheare a light on this one ? 
( First  time in life i wished my f#cking holiday is over fast ) 

As far a backing plates .I think backing plates ar  a must !!!!
I ve made them myself for all of my bongo s out of 1.5mm thick steel .( a bit oversized )
I ve hammered the steel on a  kettle  shaped  wooden  mold  .
Its a slight curve but worth the work . The conform exactly.
Drilled holes,  then hardened them  myself .
Maybe a bit overdone but , nothing but the best for my love !!!!