According to the SRD on magic:
If the Components line includes F/DF or M/DF, the arcane version of the spell has a focus component or a material component (the abbreviation before the slash) and the divine version has a divine focus component (the abbreviation after the slash).
So it is not an universal rule that all divine spells can substitute material components for divine focus. Spells that require material components only, without such substitution, may exist. And indeed, True Strike requires a small wooden replica of an archery target focus, that cannot be substituted for divine focus, and Force Anchor requires a twisted nail material component, again with no “/DF” on the list.