Clem, after I accidently posted here, I looked over the thread and can give some info.
That style GT-4 wheel is available as a reproduction but there are 3 differences:
1- They are only available in chrome
2- They are a 5x114.3 bolt pattern
3- They are only available in 18x9 and 18x10 width
[This message has been edited by IMSA GT (edited 05-05-2017).]