Either in the masthead varieties of the olloy hardcover books from 1920s-1950s, subscription/invitation special publication variants that in 1990s were in all hard cover titles, to the split-hologram Taureg boy cover, there are several threads in these discussions about whether a print variation is rarer, and even when conceded to be, does that generate an premium over the value of the "reglar" issue. I think there is, others have opined not, the debate is unsettled.
On the general topic and again analogizing to the back-issue comics industry, this morning email included a noted dealer's opinions on just such. In summarizing s successful British buying tour in December 2008, the President and founder of Mile High Comics indicated he had “concentrated my purchasing efforts at the London convention at seeking out 1970's and 1980's Marvel and DC comics with British pence cover prices. There has long been a lot of controversy about British editions of US comics, with the traditional school of thought arguing that they are reprints, and as such should be priced significantly less than American editions. I quite beg to differ with that line of reasoning. I know for a fact that UK editions were actually printed at exactly the same time as American editions. This process was explained to me during the late-1970's when I actually went to Sparta, Illinois, home of the gigantic printing plant that was producing almost all American comics. Robert Craig, who was in charge of the presses, explained to me that the interiors of comics for US and UK distribution were printed at exactly the same time. The covers were then printed sequentially, with the US editions run first. Then the presses printing the covers were stopped for just a few minutes after the US run was finished, and an UK black plate (with the current Pence price) was substituted for the black plate that had US price. In my professional opinion, this changing of the black plate for British editions was the first concerted effort on the part of Marvel and DC to create variant editions. Print runs varied, but UK editions were clearly printed in far smaller numbers than US editions. My best guess is that UK editions may have constituted as few as 10% of the total print runs during the 1970's and 1980's.
As an aside, American comics with Pence prices being shipped to the UK were often sent in the lowest cargo holds of ships returning to British ports. As a result, many UK editions have water damage. UK editions are so scarce in America, however, that I really don't care about condition. I'm just happy to find them! Our experience has been that UK editions originally sold rather slowly when we first started listing them, but are now becoming increasing popular. Especially among serious fans who have completed runs of a given title (such as the first SPIDER-MAN (1963), X-MEN (1963), or CONAN (1970) series) and are now seeking all of the variant editions. I've always know that UK editions were relatively abundant in Britain, but given that I have been trying to stock our UK variants exclusively from individual issues that I've managed to find in cities along the American east coast, I have never been able to meet our growing demand for UK editions. Knowing that I can now periodically jump across to London and restock our UK editions, makes me very happy! Over time, I also hope to be able to document which American titles actually had UK editions. There may be such a listing that already exists, but to this point in time, I have never found it.” Chuck Rozanski, December 10, 2008 by electronic newsletter
Not only were there international copies of Geographics, most notable for the plain-paper stock used for plates rather than the heavier stock used for American subscribers’ copies, I think there may be more than a couple of issues with actual printing variety, though Society acknowledges only a few (Arabic or Soviet censor copies; one late 1960s were entire foreign run contains an article never printed in US edition of that issue). Like Chuck for UK Marvels and Dcs, Bill Cole, I and others have long made notation of varieties we have come across or at elast heard of, but so far as I am aware, there is no comprehensive list.
Anyone wishing to share insights or join the variant-value-added debate, you will be more than welcome