Determining A Dirt Bike Year Without Conclusive Markings

I picked up what I believe to be an 2004 to 2006 Kawasaki KDX50 for my 5 year old son. I got a great deal on it, but it needs servicing. Before buying parts, I need some help determining what year it is. Any suggestions would be helpful as it’s not on the steering column. The first picture is what was in the steering column, but the other side said it was produced by Suzuki. They had some sort of joint agreement from 04 to 06, so I assume I’ll be buying Suzuki Jr. parts.