the coach number series 24400-24459 were driving trailer thirds based on LMS standard coaches. The one I modelled is 24425, which had no duckets and was at Leamington in the late 50s. So seems there was variety in this group.
Yup - My Jenkinson and Essery's LMS Coaches - an illustrated history also has a picture of No 24413 which is ducketless. I'm making this particular one at the moment from mostly Comet bits - chosen as I can't remember where I put my packet of duckets!