Maybe not. It was intended so you never had to take your finger off the trigger for better cycling speed (taking your finger off the trigger would have been a safety thing). Of course, it did avoid pinched trigger fingers like "those other" lever action rifles.The trigger disconnects with the lever. Been told it was a safety thing.
It doesn't look like the left side of the receiver was D&T for a peep sight like older Marlins were. The rear sight notch is close enough to the receiver that I bet it came with one of the fold down rear sights similar to the ones that come on the ruger 10/22. Those are sold for around $10 or so.
Is there a standard size for the rear site notch? I have never put a site on something that didn't involve screw and rails so this is new to me. Is there measurements for the angles or something or is it standard for all notches?