Hi Craig,
The original stanchions with one oil hole were shorter than those currently available, they were fitted with shorter top bushes to compensate for the leg length difference
Or vice versa the longer legs and longer bushes work out at the same fitted length
The advantage of the two hole stanchions are that on extension oil is trapped in the space between the bushes
stopping the topping out metal to metal clashing that can happen with the one hole type legs
So fit the new longer legs and bushes and look forward to improved fork action
John