Ok... I'll help you with this. But ya gotta make a LOCAL meeting in return
Scroll down a bit and click the appropriate law source. In this case it's Revised Statutes.
Type "vehicle and firearm" in the "search for:" cell, then hit the SEARCH button...
The statute you seek(RS 32.292.1) should be the first on the list.
Short cut - http://legis.la.gov/lss/lss.asp?doc=630878
This law removes the issue of trespass if you have a firearm on certain private property in a locked vehicle. However, it doesn't keep them from firing you. It's one of those feel good laws with no teeth.