No. Even if the same implementation is bound as another name in the RMI registery, each can hold different data.
Another problem is with the "equals" method - if a client calls "equals" on two stubs, the default "equals" method that tests object identity is used, which isn't going to return true unless you have the exact same stub. "equals" isn't going to test actual data equality on the server.
Write once, run anywhere, because there's nowhere to hide! - /. A.C.