PS2 Version

[Husker2003]

I am trying to figure out which version of ps2 I have. I have searched the internet and some sites say I have a version 3 while others say it is a version 4. Hopefully someone can help me determine which version it is.
Here is the stuff on it: Model No: SCPH - 30001
NTSC
Serial Number: U2893301
Date Code: 1A
Screws on bottem: 8
(Atleast that is how many little box holes I see.)
I read that version 3 has 10 screws but the two extra arent on mine. (2 right under the front) So if more info is needed to help, just lemme know.
Thanks,
Husker2003