There has been mention of NOS vs. Assembly line parts throughout this thread. Here is an example (for the A/C people) where this comparison is very evident. The piece on the left is an NOS insulator for the low pressure A/C line. The black foam covers the copper thermal couple tube that comes off the expansion valve and slips into the low pressure line. The one on the right is an original factory assembly line issue piece. Notice how the assembly line version has the molded indention where the copper tube fits within the foam tube. The NOS foam piece is completely round and does not incorporate this molded custom feature. It is a small variation but one that is worth noting.