A difference in thickness would affect the handling.
But the original T3's did have silver hexes, the T3'11 and '12 have black hexes (same width as the original silvers).
If you have measured both types accurately and the is no difference then they are effectively the same.
Xray T4'16, T4'14 (Wet Car)
Xray X12 2016
wlrc.co.uk (West London Racing Centre)