recently I acquired a bike. It says on the frame 10/03. so I know it is a late 2003 model. The only other thing i know about it is that is has the WR sticker on the back fender. other than that I can not find anything on the bike to tell me what size it is. the person i got it from told me that it is a 450. is there any numbers somewhere on the engine or elsewhere on the bike that i can find out for sure if it is a 450 or a 250 (or any other size)? are there any differences between the variety of WR bikes that will help me to know what size of engine i have? the picture attached is my bike.