The short answer is, maybe 14.
We discussed, albeit briefly, reportedly the only
in-the-white Parker Reproduction 28/28/.410 A-1 Special ever built that Larry Baer owned and was subsequently auctioned off at a Julia auction in this thread:
http://parkerguns.org/forums/showthread.php?t=12472 This very gun is more thoroughly described and shown here:
http://jamesdjulia.com/item/2388-386/
There are some that may remember the completed 28/28/.410 A-1 Special that was offered by another seller (Griffin & Howe I recall, but could be wrong) at $50K a couple of years ago that apparently found a buyer. It, too; was mentioned in the above same thread.