In an ideal world, that is true...
One important thing to note is that the Delta only natively accepts 39mm lens mounts. If you have a larger lens such as a 150mm that is a 53mm mount which requires serious modification to the Delta to fit. For larger lenses such as 240mm, that is usually 72mm, and with the body size cannot be modified to fit the plate.
And then there are those times when you have that one, special lens. For me, it was a Wollensak that gave the creamiest finish... Plates were expensive even back then!
Factually, a lot of things can be taken care of by using thin brass sheet strips as shims to adjust the baseboard.