I'm with Caliban on this: there are two ways to interpret things. However, I choose the version where CL is 'sometimes a requirement'. Let me give three examples:
- The normal Item [Gem of Seeing] (CL > CL of spell)
IMC, it'd have a minimum caster level of 9, since that is required to cast the True Seeing spell.
- The not so normal Item [Horn of the Tritons] (CL < CL of spell)
IMC, it'd have a minimum caster level of 9, since that is required to cast Summon Monster V.
- The CL requirement Item [Ioun Stones] (has a required CL)
IMC, it'd have a CL of 12, since that is the minimum caster level required to make the item.
Because there are items like Ioun Stones (and there are a couple more of those items), where caster level is *actually in* the prerequisite section, I let the parts of the text where it says that you must meet the prerequisite CL refer *only* to those items. Items that do not list a CL in the prerequisites section have a CL equal to the lowest CL of the highest SL.
If they went through the trouble to give a specific CL to just a couple of items, then I think that they mean the CL is a prerequisite for those items only. I mean, if the CL given is automatically the required CL, then why do Ioun Stones have both a Caster Level and a CL in the prerequisites?
[edit] Though it probably isn't going to change my mind, could somebody quote the DMG where I cannot apply the "CL is a requirement to items if and only if a CL is given in the prerequisites section" reference?
Further, all items are 3.0[/edit]