I (as another former marketing professional) agree.
The 150th anniversary is the anniversary of our founding, not of all the bits inbetween. It’s a celebration of what happened 150 years ago, just like a wedding anniversary is a celebration of the wedding day. If, to pick a completely random example 🙄, the groom had a moustache at the wedding 40 years ago but shaved it off a couple of years later, looks better without it and virtually everyone only knows him without it, that wouldn’t justify airbrushing it out of the wedding photo reprinted for the occasion.