Based on 2 incomplete VIN numbers ending with 873 and 365 from japanese car sale site I have made a little discovery:

I have put them against series of possible chassis numbers sequences (6000XXX-6030XXX)*  and every single 2.0 V6 TB car found this way had this version code:

163.819.0.0 – GTV 2.0 TB V6 MEDIO

and most had 446 Anthracite Leather interior code

*6030XXX represents about a turn of 1996/1997 and cars have 1st series dashboard before MY’97, so there is no point going further