The stock correct lugs are flat with a washer and are not acorn style.
the acorn style locking lugs were for the 350 not 370, there was a tsb to correct this
Only the early 09's had this issue, so any available aftermarket lugs must be a flat washer style to fit correctly on the stock ray wheels.
http://www.the370z.com/images/servic.../NTB09-024.pdf