Descriptive Bibliography p144 describes it as "Maps as for A5e", and A5e entry says "Maps drawn by Christopher Tolkien, as for A5a except with revision to Shire map". So it appears the general map would be the same as in 1st edition. VT 42/27 (EN4) also says "No such corrected edition appeared in 1969, or during the remainder of Tolkien's life".

However, LRRC p649-50 says "I find on the map with corrections that are to be made for the new edition to appear at the end of this year [the India paper edition, Allen & Unwin, 1969]", and "The names Swanfleet and Glanduin (misspelt Glandin) were added to the general map as revised for the edition of 1969, but in the wrong location", which appears to be adopted from UT, though CT didn't specific which edition:

It seems that in 1969 my father communicated to Miss Pauline Baynes certain additional names for inclusion in her decorated map of Middle-earth...‘R.Adorn’, ‘Swanfleet’, and ‘R.Glanduin’. The last three of these names were then written into the original map that accompanies the book, but why this was done I have been unable to discover; and while ‘R.Adorn’ is correctly placed, ‘Swanfleet’ and ‘River Glandin’ [sic] are blunderingly placed against the upper course of the Isen.

Glandin is only mentioned once in Descriptive Bibliography. p150-1 says: Folio Society edition (1977)...The maps were redrawn, giving the river Anduin two more tributaries in the Brown Lands, and mislabelling the river Glanduin 'Glandin'.

So my question is, when were ‘R.Adorn’, ‘Swanfleet’, and ‘R.Glandin’ (sic) added to the general map? 1969, 1977 or otherwise?