Of course not.
The Front Sight on the Stock III is dovetailed in, and accepts both Tanfoglio's factory FO Front Sight and Hennong's FO Front Sight and the gun is still production legal.
Under IPSC Production rules, you can basically put any sight on an approved gun; so long as you don't alter the slide of the gun.
With the Stock III, it's already set up for you to pick and choose different sights.