Hi Harmeet,
6 hexadecimal characters are 24 bits. The last 24 bits of the MAC address is the “vendor assigned” part. If you have two network cards from the same vendor then the last 24 bits should be unique.
Theoretically, it could be possible that you have two network cards from different vendors that have the same 24 vendor assigned bits but the odds are extremely small 
It is possible though to have two IPv6 addresses that use the same solicited node address. This is no problem though…both hosts will listen to the multicast group address and if needed, discard the packet that isn’t for them.
Rene