DCC does
not. This has been a point of debate at least since DCC (2012) chose to use a different set of six, retaining only two of the classic six (although two more are mostly synonymous terms). I don't think there's any consensus, although the coinage "nuSR" for games which make substantial innovations away from TSR mechanics is indicative that a least a fair sub-set have reservations about it. That being said, those games definitely fall within the broad marketing umbrella.
Subjective. The books are simply an Old School game. But your game at your table might be OSR in philosophy or alignment (

)if your intent is to revive interest and understanding of the old game, and/or if your DMing is consciously informed by insights and ideas from the OSR movement.
As an example, when I was a kid I bought into a lot of the arguments that XP for Gold was dumb. That it made no sense from a diegetic perspective. The concept of xp for finding a magic item was equally nonsensical. Coming back to older editions through reading OSR blogs and forums, my perspective changed and I became much more open to the elements of genre emulation through mechanics and of incentivizing player behavior through the reward structure. When I run B/X it's definitely using and informed by ideas from the OSR movement, even though B/X itself is simply an old game. But a grognard who never left AD&D in the first place might object if I describe his table/house game as OSR- his has not been revived, it's simply endured!
Again for me the deciding factor would be whether the conversion and play were influenced by Renaissance ideas. If our aforementioned Grognard who never left 1E saw a copy of Curse of Strahd on a store shelf and decided to convert it to AD&D because he enjoyed the original Castle Ravenloft, that (by my standards) would probably just be Old School.