I was actually gonna question this "poll". I guess determining the group opinion has merit, but certainly as JDW points out it is a question easily settled with some documentation from Apple, some of which may be found at the Stanford Library. Though, as JDW also points out, the definition of rare cannot be settled by one aspect alone, nor have the same meaning from one-person to the next. Though I think we all agree, most eBay retailers mis-use the word on average.
I would tend to agree with this statement in principle based on sheer numbers actually manufactured. Certainly I have seen a paucity of 128K branded Macintoshes on eBay as well. Technically speaking, however, "manufactured for a far shorter time" is inaccurate as I understand it. The 512K was introduced in September 1984 and presumably the 128K donned the additional badging at the same time. The 128K was discontinued in September 1985, 1 year later. Since the original Macintosh was only sold from January 1984 to (presumably) September 1984, it was the original that sold for a far shorter time than the re-badged 128K. However, I doubt the re-badged 128K sold 70,000 units in the entire year it was in production, much less the first 3 months.