There's a related question about editing the text of spam: Should spam posts be edited?. I've always understood this to include any sort of edits on a spam post, including tag edits. The tag exert for the Stack Overflow [spam] tag includes an explicit warning
DO NOT USE THIS TAG ON QUESTIONS THAT ARE SPAM, we have a special flag for that!
I recently noticed that an obvious spam post on ExpressionEngine Answers SE was treated exactly the way it is not supposed to be treated on Stack Overflow - a 3000+ rep user has retagged the question as [spam] and voted to close it seven hours after it was posted.
Should questions that are spam be retagged as [spam] in addition to flagging as spam?
This is not the same question as Should spam posts be edited? as that question is about editing out the text of spammy advertisements. This question is about leaving the text as-is and retagging the question as [spam], presumably to adjust its visibility on the site or bring it to the attention of users who might be interested in flagging it as spam.