It's a production art piece with instructions on coloring pencilled in by Woody Gelman. Howser was a rookie in 1961 so they probably took an old minor league B&W photo (or possibly one in KC duds in Spring Training since he's in the fifth series I think) and executed the Flexichrome coloring process on it, possibly with an airbrush assist. That artwork appeared in the 1989 Topps Guernsey's Auction Catalog (page 65, Lot C10), you can see the lot number on the sticker. I suspect there is a COA on the back or if not, one was originally included by Topps. That's a ridiculously neat piece, super colorful. It sold for $1,800 in 1989, plus 10% BP, which was one of the higher prices for common Flexichrome art in the auction.
I posted about Flexichrome a few years ago, it's a labor intensive process for sure.
http://www.thetoppsarchives.com/2011...rome-away.html