Registration Not Matching Up?

[VeYzZii]

Hey guys. I am in the market for a R32 GTST.
I have been looking around and have recently found a couple of interest. I wanted to get abit of information on each and have run into something that is confusing me.

One of the R32s is this: http://www.gumtree.com.au/s-ad/kemps-creek/cars-vans-utes/nissan-skyline-r32/1024553592

When i go to MyRTA to check registration and such, and put in the Rego plate, i get this:

1989 RED NISSAN R13 P/CAR S SEDAN
VIN/Chassis: ********9042

According to the seller, the car is a 1990 Skyline, that's all he says. But i don't understand what a Nissan R13 P/CAR is?? Could somebody shed some light? Is it a GTST?

Also, this: http://www.gumtree.com.au/s-ad/fairfield/cars-vans-utes/1992-skyline-r32-gtst-rego-nov-13/1015003282
Is a 1992 GTST, registered as:

2007 WHITE NISSAN SKYLINE SEDAN
VIN/Chassis: ********6766

Is something shady going on, or is it RTA error? Could i run into trouble soon if I where to purchase one of these?

Regards, Vee.

[r32-25t]

Most if the time the rta has the compliance date and all skylines are regarded as sedans to the rta

[VeYzZii]

The Sedan bit is fine. The other GTSTs are registered as 19XX Nissan Skyline Sedan.
But what is an R13 P/Car?