If it is a completely new item, then the answer is 'Yes' : under 63.1, it would be a change to forecast Defined Cost + Fee and this new rate would take the form of an addition to the BoQ which could be as a lump sum (under 63.13).
If there was a wrongly defined rate i.e. defined in WI as Stainless Steel, but listed in BoQ as galvanised and it was clear this description was meant to apply for the stainless steel, then it would be the change in Defined Cost e.g. if all bolts, lightbulbs, cost of fitting etc stayed the same, then it would just be the extra cost of stainless vs galvanised column + Fee.
If on the other hand, the PM was introducing a brand new item into the Works Information and not deleting anything, then they would be worked up from scratch. which there was no rate