Yes you can. I replaced the OEM sights on my Henry .22 with their fiberoptic sights. It’s a big improvement. https://www.amazon.com/dp/B01MZB9JQX/re ... UTF8&psc=1
That said, on the Marlin .45-70 I used to own, I replaced the rear sight with a receiver-mounted Williams WRGS-336 adjustable peep sight, and the front with a fiberoptic sight I bought on eBay. Here’s the complete package on Amazon…
https://www.amazon.com/dp/B0028MAU2G/re ... F6P857VP3B