There has never been a white Meisterstück. The Meisterstück line was made in black precious resin, to which are added the Solitaire versions in precious metal; pale body colours are no part of this range. Anyone who sees a white or beige pen of Meisterstück-like shape, in a size between the 145 and the 146, is therefore in all probability looking at a piece from a different range.
The likeliest candidates are the Generation and Noblesse series, which were made in pale tones with gold-coloured furniture. Conversely, a pen expressly offered as a white Meisterstück is reason to examine the inscription and the model number with particular care.