In JW theology, "Other sheep" do not exist apart from the "Great Crowd" in the Christian Era
You might be right, the two terms define sub-groups of the "Earthly Class". The great crowd are only mentioned in Revelation aka "the Lord's day". There really is no Great Crowd before Armageddon*, because they come out of the great tribulation, and that has not happened yet.
There is the rub for wt, although they deny there was an Earthly Calling before 1914-18, WT theology implies, that, with perhaps 134 000 sealed/dead before 1914, the m/billions of previous partakers, if they did not commit the "sin against the holy spirit", must be resurrected on Earth.
OS, whether they, or wt likes it, or not. There will be millions of partakers in paradise!
All earthly-bound humans, aka the 12 Tribes of Israel, are of the non-anointed Sheep, or wt's Other Sheep.
the real OS are Cornelius and later gentile anointed. bsw.
* wt 1995 April 15, Question from readers. right column, par 3.