Good Point John!
As pointed out in another post, this has all been discussed before at various times. I might note (Earl might have some more info) but I have a set of the DRGW Handlin Buck Radial Class Lamps that were converted from Karosene to electric at some point. When this was done, the original chimminy was left on the lamp. I have also restored another set of these lamps that were also converted to electric. On these lamps, the DRGW simply removed the chimmney and cut off the top (that is marked Handlin Buck) and brazed it to the top of the main body of the marker. This creates the shorter version of the radial marker. I don't beleive Handlin made them that way....it was just the result of some of the conversions to electric.
Also, the DRGW used both types of class lamps, radial and round lens. All of these class lamps would get broken, removed, traded to other engines and replaced in many ways. Any type could have been on any engine at any particular time.
Mike