I sent the ebay pen and question to noted Holland collector, Jack Leone. Here is his take...
David,
Had a quick look at the pen at this eBay link, and - in my opinion - it is not a John Holland pen, just the nib. I believe the seller has described it properly.
A couple of comments:
1) Holland eye droppers of this era with the open filigree overlays were pretty consistently in the pattern of my Holland overlay that you posted on FPB. All of mine (dozens) have the cap top covered. The pen on eBay is a different pattern, and this is the main reason that I don't think the cap & barrel are from Holland.
2) There is no set pattern on whether the overlays have a Holland imprint - some do and some don't. However, you can usually (but not always) find a Holland imprint on the hard rubber barrel, underneath the overlay.
3) i also check the design of the section and feed (hard to describe in words what 'correct' looks like.) Occasionally, the earlier feeds were imprinted with the Holland name. The end of the barrel often have a size (e.g. 52, 54, 74) imprinted.
4) According to the records at the Cincinnati Historical Society, 2 of John Holland's sons lived in Concinnati and one (James) lived in New York City. It is apparent that all 3 were part of the business. I suspect (but haven't yet proved) that James managed the business relationship with manufacturing jewelers in NYC. I believe that many, if not all, of the Holland overlays were made in NYC, and mounted on caps & barrels produced in Cincinnati.
For example, the repousse taper cap in the photo you posted looks like work from Heath. The 'poinsettia' pattern on the 'saddle' filler (pull filler) looks like a Carey pattern.
I'm not an expert on Parker or Waterman's overlays of the era, but the style and technique of the metal work looks so similar, that I wonder if all the major manufacturers used the same group of manufacturing jewelers in NYC , or perhaps in Rhode Island where A.T. Cross got its start. Don't really know ... an opportunity for further research.
By the way, James clearly managed Holland's export business. He also kept a keen eye on the competition. I read a letter that James wrote to his father suggesting that Holland produce and sell an accessory clip like Waterman's was doing. This was the genesis of the Holland 'Grip Clip'.