Fibre Optics?
Is it an OLD pre-B (with a staked front sight) or a newer pre-B (Transitional), with the lengthwise dovetail?
If its the old style front sight, you'll can probably find one for a 1911 that will work. If its the new style sight, CZ offers one, as does Angus Hobdell, here on the forum (Ask Angus area).
Your gunsmith should be able to determine what height is needed.