Yes, but it's not clear to me what the conclusion is, as some part said that cdecl is specific to i386, and as it was mentioned that other callbacks did not have a calling convention and has been included with `CALLBACK`.
Without any other evidence, I'd honestly just assume they're wrong. I've probably incorrectly added stdcall to some callbacks like that myself, so I wouldn't be surprised if others have as well.
I don't know how stdcall can be correct; if Windows programs are written that use those callbacks they'll be cdecl.
And yes, the stdcall/cdecl distinction is specific to i386, though I'm not sure how that's relevant?