Since no one has jumped on this I’ll give it a shot.  Short answer is a pretty strong “yes”  on losing the lockup by changing the link to lower the breech block.

I would need to ask.  Has the link been replaced already in order to fix the lockup?  This would probably have raised the breech block.

Without getting too deep into the Ballard BB setup there are 5 points that are required for a Ballard to be correctly adjusted.  The Breech Block tail, the area directly behind the angle face, the angle face, the head space and then the link.  The head space is actually two parts…proper head spacing and the vertical spacing in alignment to the barrel breech.

While I don’t agree, the following has been done.  In your guns case it would allow you to check some of the above boxes.  

If you can find a screw that fits the threads for the tang sight hole, I believe the front hole.  Screwing it clear in, it will contact the top of the breech block.  Lower the bb and adjust the screw in until the firing pin is correct.  But, more than likely the lever will not close.  Some use this method to adjust the lockup and as far as I’m concerned it’s an improper fix.  For you, it will help diagnose the issue.
Bob

One more question.  Does the breech serial number match the action number?

Also, if you do the screw test, don’t force the action close, you may damage the breech block.

Thank you both for your input.  The rifle does fire ok and the cure might be worse than the ailment.  I think I will let it go until it becomes a problem.
Charlie