(I apparently ordered mine without one, but) In reality, it is just a series of very easily removed fasteners.
92NSX can tell you the shop manual page numbers which show which fasteners affix the spoiler to the front.
Be aware that without it, you can/will scrape the front chin...arguably a more concerning bit of damage.
You might want to use a plastic material as a buffer between the spoiler and your dirt roadway rather than run risk to the chin.
- doc