Spoiler
Lois Maxwell and Desmond Llewelyn were never credited in this way either.Also was Lee one of the first people to receive this sort of credit? Listed in the opening titles by character name? I know that Lawrence of Arabia credited Sharif and O'Toole by character name.
Interestingly enough Lee and Dench are not the only actors to be billed in the main title by character name. Since LALD the actor playing Bond has been credited by character name. Besides that there were Blackman and Frobe in GF, Villechaize and James in TMWTGG, Lonsdale and Kiel in MR and finally Newton and Armendariz in LTK.