Topdressing has its place but I can't imagine it changing anything beneath the existing soil line. Chemical adjustments, possibly yes, and core aerating followed by topdressing may help with that.
I am uneducated about meals and glutens but from what I have read on the forums here their use does not pass the smell test with me. Same with molasses. Even if they were incredibly effective I do not believe it would change anything below the soil line.