I doubt a Mog is still using genuine sealed beams, they would be very old & the lifespan was not good
Mine were still working fine after 47 years - only did the swap as I wanted the ease of a H4 bulb as they're available in most garages and I do a shed load of touring.
You're right, I have a pair of genuine Lucas units dated 1967 that still work, saved for Mini concours comps, but the replacement stuff is a bit naff so for daily use I run with H4 conversions
