If your 264 ilvl boots are for tanking or for healing and you roll "need" on the dps boots, then you don't have to worry about anything. However, if you have already equipped a better item (in terms of stats) and you roll "need", I think it qualifies as ninja looting, because you don't really benefit from it. The point of rolling NEED is
to have an upgrade for your MS. If you roll "need" on an item and you already have a better one equipped, what would you do with the said item? Sell it? Disenchant it? Use it for transmog? In all of those cases GREED is the only allowed roll option.
[Edit] I have the feeling, that you aren't asking a general question, but more like describing a past event. If this is the case, could you please give more info about the two items? There MIGHT be a chance, that this information could change things. For example, I
personally consider
https://wotlk-twinhead.twinstar.cz/?item=47581 to be inferior to
https://wotlk-twinhead.twinstar.cz/?item=50264, because hit rating is more important than haste for gearing leather-wearing dps and the gem slot might not be enough to satisfy the need for hit rating (if the player's gear doesn't provide enough of it).