It doesn't really work like that Tuoma, the geometry of a person is controlled by morphs, and each look is different as to how many morphs are being combined. If the morphs used are the built in ones, then you can select the active morphs and manualy apply them to the new model, after zeroing out the lip morphs used on that look. However most looks have the geometry baked into individual head and body morphs. Even if you isolated just the lips on one model, applying it to another look would add it on top of the existing morphed lip geometry.
In theory you can export morphs from look1 to daz and reset the morph delta's for everything but the lips, and do the same for look 2. If you then set the morph for look2 to -1 it would remove the existing geometry, and you could apply just the lips of look1.
That is a complicated process though, and would need to be done for each look.
If you are not talking about the morphed shape of the lips, but just the textures, that is doable with image editing software.