That's correct, Minister. With a stock of over 400 locomotives and the lack of money in those days, overnight repainting was never going to happen. What I had in mind the above, though, was locos that remained well into GSR days, or even into CIE, which never were repainted in grey at all.
90 and all its sisters received grey before withdrawal.
As one might expect, locos on the narrow gauge lines and the W & T took a while to all be repainted. Former GSWR ones had already been under the grey sheep-dip treatment since about 1918 by the time the GSR was formed. Jhb171-Senior has no recollection of seeing a former DSER or GSWR loco still in pre-grey liveries, despite bring very familiar with both the Harcourt Street line, and the innards of Inchicore Works, from the early 20s. He does, however, vaguely recall GSWR coaches still in their old livery. Apparently there was an old passenger van in tattered GSWR livery still pottering about in or around Kingsbridge well into the 30s. Probably others elsewhere too.