I am certain that Dowlan came up with the technique entirely independently, and to him much respect and admiration are due for a whole host of reasons. Hell, his story (watch the YouTube video) about being watched in 1951 (I was 4 years of age then and hadn't yet mastered ratamacues*) by Perrilloux prior to being judged by Pratt. Well, that's the real deal. Perrilloux was not easy to please, to say the least.
And thanks go to Larry McCormick for his efforts to record and preserve drumming history.