Console Version?

[Shmo]

I myself own a ver. 4 system and have a no solder chip. A friend asked me to mod their system and I know it needs to be at least a ver. 4 to use a non soldering chip. I have read info from a site that said if your system has 8 screws on the bottom it is a ver. 4 or higher . Since their system doesn't have an R I know it is earlier then a ver. 5. Could someone confirm this for me or give me a site that explains the signs of knowing what version console a person has.

Thanks in advance