Welcome to the site !!
The bike "should" have a sticker on the frame spar that says (for example) 2006 CRF450R or CRF450X
It would look like this and should be present on all years and models , it will either be on the left or right frame spar
If for some reason that is missing or damaged it can also be identified with the vin # , located on the right side of the headstock , for a R the vin # would have PE05 as the 4th thru 7th digit , as well as the 10th digit would be a 6 for the year , indicating a 06 450R
For a X it would be PE06 along with a 6 as the 10th (year) digit ..... Indicating a 06 450X
Hope that helps ....
