PCIE Gen 2 Intra-Pair Skew
The propagation velocity on most flavours of FR-4 is about 160 picosecond per inch (surface) to 175 picosecond per inch (internal).
.06 inch (60 mil in American parlance) gives about 9. 6 picosecond of skew.
Note that the 8 nanoseconds of skew is interlane skew. Within a pair you need to keep the skew below 10% of the unit interval which for 5Gb/s requires skew of less than 20 picosecond which you meet.
Any skew will cause differential to common mode conversion which can cause EMC related issues, but it is completely design dependent.