I can't say for sure, but the ending quote from the article “I have to share the credit,” Bradley joked. “I may have invented it, but I think Bill made it

I can't say for sure, but the ending quote from the article “I have to share the credit,” Bradley joked. “I may have invented it, but I think Bill made it famous.” seems to support the theory that he reinvented it independently. I'd be interested to know who at MIT picked the key combination Ctrl-Meta-Ctrl-Meta-Rubout for the Lisp Machines.