Yes, a Dell installation disc will not require a product key for activation, as it uses an embedded self/auto-activating key used by OEM's to simplify the activation process.  Although it does not require a key to be entered, the OS installed must match the version of Windows listed on the COA/license sticker (or qualified downgrade).
A friend of mine used a DELL  XP Pro reinstallation disk on a Win (* and a Win XP Home computer and it never asked for a product key. So is it true that a DELL reinstallation disk in a DELL computer doesn't need a product key ?
DELL in DELL