[morzh]

As long as this is strictly B+, I guess it is not that bad.
However you also have to take into account the fact that the Mains voltage is higher than it used to be by up to 15V (116-124VAC vs 105-110VAC back then).
Go by the datasheet; if the resulting voltage is up about 25-30VDC from all factors combined, I would tru to bring it down as this is up to 25-30% from the previous one, meaning the same percentage of the dissipated power. While tubes will take that (they obviously were not used at the upper limit of the plate voltage), this rise in dissipated power will shorten their life.

So if it is the daily driver, that's one thing; if it is a demo unit you turn on once in a while, its another thing.