Further down this page, there is some discussion concerning a "horse racing" 11C on eBay. I ended up buying this 11C, and wanted to post what I have (and have not) found.
There is, in fact a template on top of the regular face plate. The template looks to have been professionally die cut, with an adhesive backing, not glued on at the kitchen table. Also, the printing on the template looks like a "factory" job. The calc passes both tests, and seems to function simply as an 11C.
I found another reference on some other discussion site to another one of these having come up on eBay some time back. The discussion was similar to what we saw here. But the point is that there has been at least one other auction of this type of item - Yes, maybe this very one.
Something else I found interesting, and possibly related to this calculator, is that HP apparently sponsors the "Galway Plate" horse race. I don't follow horse racing, and have never heard of the Galway Plate, but see http://sport.guardian.co.uk/horseracing/story/0,10149,1009359,00.html to see what I am talking about. Perhaps HP put these out in association with this horse race. Just speculating.
Does anyone else know anything about HP's association with horse racing?