I think the answer to your question will be "Yes, what you said"...You ask if you should do "A" or "B". Based on how you described each set of tasks, I can't really see any difference, however. Can you add a little bit more context?
But in the main, all you need to do is stop Tableau, point to the "new" certs where ever they live via the Config tool, then restart Tableau.
Make sure that where ever the new SSL files are, that the service / account that's running Tableau can access them..
Place the certificate files in a folder named SSL, parallel to the Tableau Server 10.2 folder. For example:
C:\Program Files\Tableau\Tableau Server\SSL
This location gives the account that's running Tableau Server the necessary permissions for the files. You may need to create this folder.
From: Configure External SSL
Were you able to get the new SSL files going ok?