Weatherby Mark V thread are 16V , shank is .700 long and o.d. is 1.060.
I, at this time don't have the Vanguard/Howa thread without going to the shop and digging through my barrels. But, by checking your barrel against Mark V specs. you will be able to tell.
But there is much more work to be done to a barrel other than just screwing it up - the Mark V barrel has some special cuts ar the rear whereas the Vanguard, according to my memory, does not.