I think for legacy loot mode (old raids) the total drop is same for the raid itself; so there is 0 benefit to bring more than 1 from a gold point of view (except maybe clear marginally faster; and then maybe be able to learn drops based on armor type etc for mog, but not for gold)

I'm not 100% sure though and that'd be a quick test, run it once with 1 guy, once with 5 or more and total all the drops ?
(I'm fairly positive for raw gold per boss; but less sure about other drops)