Glass manufacturers did not usually add metalwork themselves. Nigel is being a bit of a purist, as the base with comport is how it is shown in the Walther catalogues. But if the hole for the cable in the base is not drilled post pressing, she was also made to be a lamp base, but there was nothing to stop hole being drilled. The glass manufacturers' catalogues never wrote in stone what happened to the products they made. The glass manufacturers sold to wholesalers, who may or may not have tweaked what they bought, and to retailers, who sold as supplied. Business is business.
I don't know if the shade is Walther or not. The wholesaler will have ordered the bases from Walther, the shades from Walther or another supplier, and the gallery from the metal basher. Then either assembled them or had them assembled before selling them on as complete units. These base were also probably sold retail as candlesticks.