A fastener assembly comprising: a panel fastener including a panel retention tab , a first panel retention surface , and a second panel retention surface ; a lock pin including a flexible arm and a retention tab , wherein the flexible arm includes an angled wall and an end surface and the retention tab includes a retention surface , the lock pin being insertable into the panel fastener to a first position and a second position, characterized in that the flexible arm is configured to: upon insertion of the lock pin into the panel fastener in a first direction to the first position, flex inwardly and then outwardly to bring the end surface into engagement with the panel retention tab , the lock pin being axially retained within the panel fastener at the first position via engagement between the end surface and the panel retention tab and engagement between the angled wall and the second panel retention surface ; and upon insertion of the lock pin into the panel fastener in the first direction to the second position, flex inwardly to allow the retention tab to pass into the panel fastener to bring the retention surface into engagement with the first panel retention surface , wherein engagement between the retention surface and the first panel retention surface inhibits removal of the lock pin from the panel fastener in a second direction opposite to the first direction. a panel fastener including a panel retention tab , a first panel retention surface , and a second panel retention surface ; a lock pin including a flexible arm and a retention tab , wherein the flexible arm includes an angled wall and an end surface and the retention tab includes a retention surface , the lock pin being insertable into the panel fastener to a first position and a second position, characterized in that the flexible arm is configured to: upon insertion of the lock pin into the panel fastener in a first direction to the first position, flex inwardly and then outwardly to bring the end surface into engagement with the panel retention tab , the lock pin being axially retained within the panel fastener at the first position via engagement between the end surface and the panel retention tab and engagement between the angled wall and the second panel retention surface ; and upon insertion of the lock pin into the panel fastener in the first direction to the second position, flex inwardly to allow the retention tab to pass into the panel fastener to bring the retention surface into engagement with the first panel retention surface , wherein engagement between the retention surface and the first panel retention surface inhibits removal of the lock pin from the panel fastener in a second direction opposite to the first direction. upon insertion of the lock pin into the panel fastener in a first direction to the first position, flex inwardly and then outwardly to bring the end surface into engagement with the panel retention tab , the lock pin being axially retained within the panel fastener at the first position via engagement between the end surface and the panel retention tab and engagement between the angled wall and the second panel retention surface ; and upon insertion of the lock pin into the panel fastener in the first direction to the second position, flex inwardly to allow the retention tab to pass into the panel fastener to bring the retention surface into engagement with the first panel retention surface , wherein engagement between the retention surface and the first panel retention surface inhibits removal of the lock pin from the panel fastener in a second direction opposite to the first direction. <EOS>