The auction in 2010 only included three pictures of the Robert May Hawken. The one above and close-ups of the barrel stamp and patch box.
John Baird included a few photos of the rifle in his first book. Page 37, Plates #54 and #55 are details of the patch box and lock. Page 89, Plate #130 shows Robert May holding the rifle.
The book
The Hawken Rifle: Its Place In History by Charles E. Hanson, Jr. has line drawings of the engraving on the patch box, lock, breech tang, and trigger guard on page 43.
These are all the published pictures of the rifle that I know of.
Baird doesn't mention it and may not have known it, but Robert May restocked this rifle while he owned it. This was noted in the description for the 2010 auction. All the metal parts are original, but the stock is not.
There are two other J&S Hawken rifles that are very similar to this one. One is pictured in Jim Gordon's book, page 367, and the other was recently donated to the Autry Museum in Los Angeles by the Gamble family.
Gamble Family HeirloomThis Gamble family heirloom is on display at the “Western Frontiers” exhibit. Signed on the top of the barrel, “J. & S. Hawken St. Louis,” and bearing an engraved hammer and lockplate stamped “WOLFE & BISHOP WARRANTED,” this .58 caliber Hawken caplock plains rifle is unusual due to its engraved iron patchbox with a buffalo motif (see inset).
The most obvious similarity among the three is the patch box. The lids are the same. The finials are similar with the one in the Autry Museum the most elaborate. All three have a buffalo engraved on the patch box lid.
The snail on the breech of the three rifles are similar with the Robert May snail more elaborate. Both the Robert May Hawken and the Gamble Hawken have “WOLFE & BISHOP WARRANTED” stamped on the lock plate. The trigger guard, butt plate, and nose cap follow common J&S patterns. The Robert May Hawken and the one pictured in Gordon's book have the same engraving pattern and style on the tang and trigger guard. Not sure about the one in the Autry.
It's unusual that three fancy J&S Hawken rifles that are so similar have survived. Survival rates of J&S Hawken rifles are low. One wonders just how many of these fancy rifles in this particular pattern that they actually made.