python 581xp neutral safety wire

I am installing a Python 581xp remote starter into a 1996 Chevrolet Lumina sedan 3.1L.  On the wiring diagrams I have seen, the Lumina does not have a neutral safety wire.  Is that correct?  How do I prevent the system from starting the engine while the transmission is in drive?

Thanks!

What color is the starter wire in the vehicle?  Yellow or Purple.  If it's yellow, I think you're ok.  Purple.. you'll need to make an interface,  because it'll be able to start in gear,  You can do the whole install and test it.  If it starts in gear, you can wire an interlock in.