In the United States, parties are not required to register their marks to obtain protectable rights. You can establish “common law” rights in a mark based solely on use of the mark in commerce, without a registration.
Merely putting (TM) after a novel, otherwise unused name connotes legal trademark protection in the US.
Yes and no. If you have been using a name on a product and can prove that you were Distributing materials with it used before the other company started using it, you will win. I have just recently dealt with a client who actually did register the trademark and another much larger company uses the same word as a product name and started legal action. Even with the register trademark they had to obtain old copies and original marketing artwork to illustrate when they started using the word