It can't possibly be RCA with a Mdina label.
(I still can't see more than one image in the first link, so I can't comment on the marks.)
There is no telling what marks some dodgy geezers will try to put on bits of glass. Just because they've heard that a Harris signature is worth something doesn't mean they won't try to shove it on something inappropriate.
I don't imagine dodgy types worry too much about correct information.
I've seen things claiming to have Harris signatures that did not resemble anything Maltese far less a Harris signature (they couldn't even spell "Michael") and Lalique enscribed on a very common pressed glass pink vinegar/oil bottle.
This is my bowl.