Marble's may well make a tang sight that would fit it; I believe they already do for the standard Big Boy rifles. On my H001T, which has nearly the same sights as the centerfire rifles, I had my best friend whip a 'peep' replacement for the factory rear sight plate. It works very well with the factory front bead, and despite being far forward on the gun, is fast and precise to acquire
As both the front and rear sights are dovetailed into the barrel, one could readily replace both with any number of aftermarket components. Check around, there are many options out there.
If you are like me and get sold on the forward peep sight concept, Tim Skinner (
www.skinnersights.com) makes some nifty stuff, and at affordable prices too. I haven't ordered from him yet, but many have and reported positively on his work and service. Might be worth a look.
Kind Regards,
~450 Marlin~
P.S. Regarding your query about peep sights for the rear scope mount holes, I would contact Henry and ask them about it; they should be able to point you in the right direction.
