The Fiber optic front site offered on some of the Buckmarks over the counter are good. They are also available from Browning to add to any of thier Buckmarks.
Are they worth it? That's entirely up to the shooter. Older shooters like myself who's eyes aren't what they used to be or shooters that ferequent indoor ranges or under low light conditions or racoon or other varmints at night would benefit also. I've a Buckmark URX target and shooting indoors I had difficult time seeing the front blade in those conditions. For me a little Bright Sights paint did the trick but I'd buy a fiber optic model if I do get another.