@Johnnypenso is correct. There are a backlog of SEMA winners yet to come to a GT game, specifically every event winner after the Pozzi Camaro.
These are the SEMA Gran Turismo Award winners by year (
source):
2003 - Buick Special '62
2004 - HPA Motosports Stage II R32
2005 - AEM S2000
2006 - Art Morrison Corvette '60
2007 - HPA Motorsports FT565 Audi TT
2008 - High End Performance G37
2009 - Grand Touring Garage Mustang Trans-Cammer '70
2010 - Stielow Engineering Camaro '69
2011 - Mary Pozzi Camaro RS '71
2012 - Eckerts Ford Mustang Mach Forty '69
2013 - Chris Holstrom Chevy Nova '67
2014 - GoPro Rampage Camaro '70
2015 - Sung Kang Datsun 240Z '73
It's actually more likely that we won't see the Datsun in GTSport considering PD's track record with getting these into games. GT6 only saw the additions of the 2010 and 2011 winners when it was release in December 2013.