Duplicate all products from one Category to another

[shags38]

Hi - found this thread which explains the process, second page near the bottom, however it raises questions also https://www.zen-cart.com/showthread....-in-bulk/page2

Using that process refers to 'Linking' products, not 'Duplicating' them, albeit I think it can also be used for Duplicating, just unsure - if I follow the process of creating a new category, then linking all products in one category to that new category (which I have actually done) then the next part of the process , below, raises a question;

Reset the Master Categories ID for All Products in Category:
Reset ALL Products in the selected Category to use the selected Category as the new Master Categories ID ...
Example: Resetting Category 22 would set ALL Products in Category 22 to use Category 22 as the Master Category ID

Question: does resetting the Master Categories ID for the linked products in the new category have any effect whatsoever on the status of the Master Categories ID of the products in the still active original category from which the products were linked? Does it change that Master Categories ID as well ? I need the same products to have 2 Master Categories ID, one in one category and one in another. My interpretation says this is what happens if I follow the above step but I need to be sure :)

cheers,
Mike