Blue Orange
Gone to Texas
The books back you up! From the 2e PHB (1989): "This is not a race in the true sense of the word: caucasian, black, asian, etc. It is actually a fantasy species for your character -- human, elf, dwarf, gnome, half-elf, or halfling." The 1e PHB doesn't address this issue at all--it simply lists 'racial stocks' such as dwarf, elf, etc.As an old time gamer myself (started playing in 1980), I think what WOTC has done is great overall. That does not mean I like everything they have done, although I do like most of it.
Before I go further I want to talk about the word "race" - From my point of view what "race" refers to in D&D is not the same as what "race" refers to IRL. Race IRL encompasses people who are all human and from different areas or cultures. For example in D&D we do not say humans native to Chult are a different "race" than humans native to Rasheman, on the character sheet both say "human" or "variant human" while IRL they would be different races.
So, yes, all human backgrounds would be considered the same 'race' as far back as 1989.