Story of my ipod nano (the new one) (skip it if you don't care

) :
I was at my house doing this work with some people and suddenly one of my friends (i dont really like her now) appears and its like "hi i came to help you

" i was like ya what ever. later she left with some of my friends to her house she was like "when you finish let go see my boyfriend!" and my other 2 friends were like yay!! . like an hour later i noticed i couldn't find my school jacket with my ipod and keys inside. I asked my mom if she saw me come back from school with it but she said she didnt remember. I was (I am) sure i had it when i came back and that i left it in my bed. After some days of looking at school, my house and everywhere i gave up and accepted that i had lost it. The thing is that like a week later this friend said that this guys stole her ipod (she had 1 too) at a party. I was like "at least im not the only one". A month later she whent to mexico and came back listening to music. i asked her if she bought a new ipod or something and she said she bought a new ipod in mexico half the price. I asked if i could see it and i noticed at first that it was the same color than mine, then when she gave it to me i saw a > shaped scrach just like the one I made on my ipod in the summer. that wasnt much, but it had a scrach at every place that mine did. Allso the apple at the back was slightly purple just like when my sister tryed to make it a berry with her pencils. I gave it back and walked away really mad i was about to yell at her stuff like "wtf this is mine give it back u #$%#$%"#%". But then i wouldn't have many chances to take it back since she could make the scraches disapear and clean the slightly purpple apple...
Now... (after the sad story of my ipod...) I want to know if that's really my ipod, i cant just go and tell her to give it back. I have the box the little manual books the 2 apple stickers that came in the box... i have all exept my ipod. is there any way i can prove that her ipod is actually mine? I want to know and if she refuses to give it back i could make her give it back. Maybe its just a big coincidence and she is telling the truth, I don't understand why she did that, she has money and she had an ipod.
plz help

is there somewere IN the ipod were i can see like the serial number or something that may prove that ipod is mine? plz help