I believe this is very good idea.
The danger that newly bought HDD will have slightly different number of sectors is real.
In Seagate case its docs refer to “guaranteed sectors” but look like this can change between revisions. Drive Replacement Too Small Error
In WB case I cant even find number of guaranteed sectors. So how am I supposed to make sure my new drive will be the same size as the old one? Even single sector difference can be a problem and since this info is not online I cant even prove something is wrong.