No, because the Lamprey Bite has a fixed strength, it is not S: User. You can give a Fateskimmer +40 quadrillion strength if you so wish, but the Lamprey Bite will always be a fixed strength value. Compare the Locus rules to the Unstoppable Ferocity errata. The rule got changed to affect the strength of the melee weapons rather than just the strength of the unit. Pre-errata Unstoppable Ferocity did nothing for Bloodcrusher's Juggernaught Horns.