HW 90 front sights

Hello fellas, 

Does anyone know what the difference is between the HW 90 front sights and the rest of the line? I contacted Weihrauch and asked, but the answer was. It does not fit. Well yeah, I already knew that. Was trying to mount the fiber optic front sight, but store sight says, excludes HW 90 and 98. How about red dot sight or reflex for this rifle? 

Thanks in advance.
 
The fiber optics won’t be as accurate as the iron sites. The stock iron sites on the whole line of HW remind me of the Finnish Mosin Nagants. Very accurate and great for quick target acquisition whereas fiber optics will tend to draw you in a bit too much. Don’t fool around with that crappy $30 range red dots. They are not air gun friendly. Go for a Hawke red dot or a Vortex. You might try just a UTG mid level (which is affordable, and though made in China it is based in the free China state of Taiwan (which is way better) and has good quality and warranty. Honestly though you can’t do better than the stock iron sites. Practice and shoot for a bit longer and you will see.