The black struts are there, it's just that the spoiler is yellow. And as Magnus and I have both mentioned before, it's likely to do with a condition of licensing with Lamborghini. The clear scans provided in the link by FatalityPitt confirms that this toy does have a licensed vehicle mode.
The trademarks copyrights and design rights in and associated with Lamborghini, Lamborghini with Bull and Shield Device, are used under licence from Automobili Lamborghini S.p.A.
Takara were initially only able to obtain rights for that vehicle for Tracks in yellow as the vehicle wasn't available in blue. Hasbro later obtained the rights to release it in blue for Alternators, then Takara later released blue BT Tracks.
The taillights appear to be a permanent fixture which are covered up in the "Super Tuning" variant transformation.
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