They have. Visually - on the order page.
These pictures were taken from Tesla's order pages today: a M3LR and MYLR side to side. All three variants of the M3 - and the MYP - have had the projector headlights for a while now, and the headlights look the same on the order page if either of those four cars is selected.
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The MYLR on the right is the only vehicle Tesla offers in North America at the moment that is 'known' to still use the old reflector headlights, which look a lot different - even in the renderings on the Tesla order pages, as you can see here. Compare the MYLR to the MYP on the website, and you'll see that the MYP has headlights that look exactly like those in the picture of the M3LR on the left.
Everyone who has ordered a M3 recently should have a rendering of their specific car configuration on both the phone and web apps which clearly show the projector lights on the left instead of the reflector lights on the right (at least mine do).