Difference between Retina Mid-2014 13" and Retina Early 2015 13" Top-Lid


New member
I found out about six months ago that the top-lid assembly for the 13" Retina Mid-2014 and 13" Retina Early 2015 are not interchangeable even though they look identical. However now I have a stack of these Top-Lids that I need to go through and they look identical. Does anyone have any experience with these and know how to spot the difference in manufacture year?