The info below may be incorrect
The model of your bros should be written on a white sticker near or on
 
the colour label (Look at the diagram below). 
The diagram below is for a Honda NT650 Hawk GT
My Bros NT400J does not have a "vehicle identification number"
 
Product one refers to the 650cc version and Product two refers to the 400cc version.
If your frame number lies between the numbers devided by the "~", then thats 
your bike
| Model | Product | Frame Number | 
|---|---|---|
| BROS NT400J | 2 | NC25 1000001~1008753 | 
| BROS NT650J | 1 | RC31 1000001~1002543 | 
| BROS NT400K | 2 | NC25 1050001~1053898 | 
| BROS NT650K | 1 | RC31 1050001~1050698 | 
| BROS NT400K 2 | 2 | NC25 1053899~1053958 | 
| BROS NT650K 2 | 1 | RC31 1050699~1050898 | 
| BROS NT400L | 2 | NC25 1100001~1101011 | 
| BROS NT650L | 1 | RC31 1100001~1100313 | 
| BROS NT400L 2 | 2 | NC25 1101012~1101231 | 
| BROS NT650L 2 | 1 | RC31 1100313~1100663 |