I looked for my 2017's Engine Number so that I could write it in the Owner's Manual and it took me quite a few minutes to find it.
On my bike (a 2017), it is located on the" Left Lower - Middle - Side, of the engine, Just in front of the left foot peg and Directly Behind the Header Pipe (looking at it from a side view). The engine number is fairly challenging to Find/See. (see attached)