I think Handlan Buck stopped making the Radial Lens Class lights many years ago - probably in the 1950's. At the end they were in the "railfan" biz making caboose markers, switchman's lanterns and such.
25+ years ago I bought a Dressel Radial Lens lamp - like a Handlan but with the usual Dressel/Handlan differences in chimney. etc. The guy I bought it from gave me new lenses that he claimed to were the last pair of lenses Handlan had in stock in the late 1970's. The lenses came wrapped in an early 1960's St. Louis newspaper.
A few years back, someone made off with some class lights at the CRRM. One of thier volunteers made some replica lamps using caboose markers and new lenses that were cast up out of epoxy.
Considering that nearly every D&RGW engine had a pair of these (along with some L&N and KCS power), it's a shame they are so rare. I've heard stories of piles of them being turned in for scrap.
I wonder is there is a big buried pile of them over where the Alamosa roundhouse was?