Does the +1 enchant bonus for masterwork weapons apply to enchantment cost calculation?

A weapon must be masterwork to be enchanted, it also must have +1 enhancement bonus before it can be enchanted. Does the +1 enhancement bonus* from being masterwork apply?

Example Calculation: +1 Benevolent Rapier

Rapier 20gp

Masterwork 300gp

Benevolent 2000gp

Total: 2320gp

*Note: This is a non-magical bonus to attack rolls