I would hope they used the 6 creed shoulder, but who knows (meaning you can use the brass and change the should location or angle).
The 6GT was made by a friend of mine, where the guys simply wanted to “not” run the dasher so hot to use it in PRS so they just pushed the shoulder out a bit on a Dasher to make the GT.
The only issue you might have of course is finding a smith that will chamber wildcats, some of them only do SAAMI work... it they used the shoulder then they should be able to use the 6.5 Creed go & no-go gauges... Saftey and consistency is always a plus, and one last thing to worry about.
