Let the buyer beware. That's particularly true when it comes to making a purchasing decision on some certain so-called error coins.
A prominent example of such apparently legitimate error coins is Panama's 1/2 Balboa struck over Kennedy Half Dollar.
For years until 1984, US Mint has produced coins for many foreign countries, such as Argentina, Boliva, China, Israel, Panama, Taiwan and Venezuela - just to name a few.*
Panama's 1/2 Balboa's composition, weight and diameter are identical to those for the Kennedy Half Dollar. This 1/2 Balboa variety was made at US Mint from 1979 to 1980 and again in 1982 and 1984.**
Over the years, a few coins surfaced where one could easily see the overstrike of the 1/2 Balboa on a Kennedy Half Dollar.
At a first glance, such errors might appear to be the result of an oversight at US Mint. However, these coins leave a few tantalizing clues that point to a different conclusion.
Each of these specimens show two different dates, two different countries (and language). The dates are different at least by a few years. The profiles of John Kennedy and Balboa are almost always aligned closely with respect to each other.
What are the odds for this particular example where a 1971 Kennedy Half Dollar would lie undetected in a holding bin or inside a machine at a US Mint for some 11 years before being struck by the dies for the Panama 1/2 Balboa?
Also, what are the odds for all these overstrikes whose two profiles would line up closely together?
It is interesting to note that for all overstrikes of the 1/2 Balboa on the Kennedy Half Dollar compiled thus far [See table.], they all show the date 1982 for the Balboa and a different date for each over-struck Kennedy half dollar.
Not long after the December 1989 invasion of Panama by the U.S. forces, an error-coin dealer, Fred Weinberg, was approached by an US Army officer who offered him a batch of such overstrikes. In his words, there were "more than just a few pieces," and Fred declined the offer as the officer was asking for too much for them.
Perhaps, for all we know, the dies for the 1/2 Balboa after the 1982 production were sent to Panama, and someone down there had a funny idea later on and surreptitiously made these overstrikes as a "midnight special." After the invasion, he might have approached and sold the overstrikes to an US Army officer.
Ever since then, somehow, these overstrikes would show up at various auctions and at coin shows.
Yet, with their somewhat colorful past, it does appear these so-called error coins were intentionally fabricated.