If you get one at wal-mart you will most likely get a V7.... So you will be fine....
The 30001R you mentioned see which one it is.......
30001R v4 = 8 Screws on base of PS2
30001R v5.x = 8 Screws on base of PS2 with three screws in top rim of expansion bay
If its the V5 you should also be fine.....