Brownells has an aperture sight that mounts to a rear scope base. You'd have to figure out your elevation on your front sight though. Maybe a blank that you could file to the correct height? Stalkingbear could probably point you in a better direction to adjust for elevation.
I'll see if I can find it in the Brownells catalog and send you a link. Their search function is kinda hit or miss...
"People live too long, dogs don't live long enough" - FTF Member-