Accurate disassembly, don't know what much to say. Like most extended sprite disassemblies, it's only useful for developers, but nice to have.
For those who wish to mimic the original spawning, the routine which spawns the vanilla version of these is at $07FC3B. It spawns four of them, each one being spawned by $07FC52. They're spawned 4 pixels right and down of the sprite slot in $15E9. The speed tables are at $07FC33 and $07FC37 for X and Y, respectively.