Sure, Tom, that may be. But then again, a free-lance artist may have met hundreds, if not thousands of clients over the years, maybe with quite a few of them having very "special" assignments. And was drawing hands a totally odd job at the time? Maybe, maybe not. Who knows.
And maybe a fine artist would pay special attention to the hands of this strange clients. But then again, maybe he was so busy getting the finger positions, cards, and angles right that he wouldn't remember a thing about the man's real hands...
As for estimating a person's age and height, this seems very thin ice to me. There's a huge subjective factor in it. Also, from today's perspective, a lot of people on photos 100 or more years ago seem to look so much older then they actually were at the time.
And as I've just learned from Joe Posnanski's interesting book, "The Life and Afterlife of Harry Houdini," even the world's most famous and most publicized artist of his time, who undoubtedly was a short man, had quite a range of heights attributed to him.
My biggest point though are the indisputable limits of our senses and our brain when it comes to attention, perception, and memory. Please feel free to take my little test on http://www.zzzauber.com
. If, after 10,000 or more hours of toying with playing cards right under our noses, we are not even able to tell which Jack looks which way or which Kings do not sport a mustache, what kind of peripheral information are we supposed to report reliably then decades after an incident?
I think it's so telling that we marvel at the few enviable people with eidetic memories, as this incredible trait is so many light-years away from our own experience in daily life.
That's why I wouldn't bet more than a dollar on the reliability of Smith's recollection. And I certainly wouldn't use them as "evidence" against or in favor of one Erdnase candidate or another.