Having no reason to look into it further all these years I had always accepted she was Marion Shilling. After all, she was there at MGM at the time in movies such as LORD BYRON OF BROADWAY. And without looking too closely there was a resemblance. But now I'm also thinking she's Doris McMahon.
There is currently a nice picture of Doris on eBay:
http://www.ebay.com/itm/DORIS-MCMAHON-2 ... 2eb508518eMore Doris pictures here, including one of her as a blonde, from HIPS HIPS HOORAY (1934):
http://www.fanpix.net/picture-gallery/d ... 716556.htmObservations after doing further digging:
She has two different IMDb listings, as Doris McMahon and Doris McMahan, apparently the same person.
One gives an obviously incorrect birth date of 1928.
Neither listing includes movies we know she's in - PLAYING AROUND (1930) and FREE AND EASY (1930). Someone needs to notify IMDb of these additions and corrections.
Coincidentally both Doris McMahon and Marion Shilling appear together in one film, the 1932 Masquers Club short RULE 'EM AND WEEP.
And that's Joseph Young (Robert's brother) with her in those shots from SHRIMPS FOR A DAY.