What it does follow from is that sentences which nominally express facts about the physical world are really expressing facts about the phenomenal world. However, my agreement is contingent upon this specialized use of the term 'physical'. If two numbers, x and y, are indistinguishable then x and y are the same number. You can't have two different number 3s. Using complex numbers one could say that an aspect of two numbers is the same while another aspect is different.
Meaning is a function of context.
A stop sign may mean one thing when posted at the end of a street and something else entirely when on the wall of a teenagers room, for example. My usage above is rather precise. If a philatelist has two copies of a stamp, and pronounces them indistinguishable, that does not mean they are the same stamp. The reason is that, strictly speaking, they are not indistinguishable. At any given moment, they will be in two different places, and that suffices to distinguish them.