So Custom Weapon Bonuses automatically apply to currently made weapons?

In Fallout 3 when you get the schematics of a custom weapon you already have you get a message indicating the effectiveness of the weapon have increase and in the Notes section of the Pipboy the schematics have a v# after them.

I am wondering however, if i already built a custom weapon like the Shishkebab and then i find and/or buy another Shishkebab schematics, does my currently built Shishkebab automatically have the bonus from my Shishkebab v2 schematics? or do i need to craft a new Shishkebab to get this bonus?