Fancy add-ons for '03 target sights?

In studying British/European target rifles, it seems like it was common to add aftermarket doodads for an extra little bit of advantage, like adjustable-aperture eyepieces or color/polarizing filters on micrometer rear sights, or magnifying lenses inside tunnel sights.

I've never heard of anything like that being used with target '03s. Did similar add-on bits exist back in the day, like an adjustable-aperture or filter eyepiece for a Lyman 48?

Merit brand adjustable iris apertures were used on Lyman 48 sights. On 1903's set up for use in competition as NRA Match rifles Lyman 48's were used
as well as Redfield Olympic and International sights.