Are you just using these yourself for single player, or trying to use them for a PW? If single player, you would be fine putting the files in your override, so long as you remember to place an altered version of placeables.2da in there as well (you'll probably need to update to version 1.69 yourself.) Just remember that you would need them in your override EVERY time you play that mod.
However, if for a PW... the safest thing to do is put those same files in a hak. Else there is no guarantee if people logging in will have them.
If you need more details, feel free to ask.
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