Yes, they're the same place. It's shown as plain Norwood Cemetery on pre-WW2 maps; and South Metropolitan Cemetery before WW1, though it was known colloquially as Norwood Cemetery even before then.
Where to post about places now in Greater London is a long-standing conundrum on all genealogy and local history websites. Comparing the lists of towns at the head of the London and Surrey forums shows that posts about West (aka Lower) Norwood, Upper Norwood and Dulwich should be in London, though I suspect South Norwood should be in Surrey as its jurisdiction is Croydon. Those of us who study Greater London areas will check for posts in the original counties also.
