Rare design for the Guards (10)

I believe the answer is:

grenadiers

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'the guards' is the definition.
The definition and answer can be both people as well as being plural nouns.
Perhaps they are linked in a way I don't understand?

'rare design' is the wordplay.
'rare design' anagrams to 'GRENADIERS'.
But, I am not sure how the anagram is indicated.

'for' is the link.

Can you help me to learn more?

I've seen this clue in The Globe and Mail.

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