Yes, I recommend staking the barrel foot to retain the link pin. The pin should be angled on the end to allow that to be done, and it should have been done at the factory. It makes no difference when the gun is assembled, but if it is not staked, the link pin can fall out and be lost when the gun is disassembled.
Normally, if the slide stop pin is inserted between the link and the barrel foot, the barrel is locked up and the slide cannot be moved. Worse, if the slide stop is inserted all the way (difficult), the gun will be completely unusable and the slide stop will have to be cut so it can be removed and replaced to make the gun workable.
But since the link was put in backward, and if there was a more than usual amount of play in the barrel, the barrel could have had enough room to move backward. When the link cleared the slide stop pin, the barrel could drop enough to unlock. Then, if the link was stuck in the upward (forward) position, it would clear the pin going forward, then the barrel foot will ride up on the pin and the slide will go into battery.
I will say that I have not tried the reversed link. But I have tried a 1911 with no link at all, and it did function for a couple of shots, working just that way.
Jim