How did you reach that conclusion? Regardless of the church wouldn't you still believe in God or are you saying that without the church you can't believe in God?
Yeah, I'd have to say that if the LDS Church isn't true God does not exist, at least in any form that we as humans would not consider to be an alien threat.
I reach that conclusion because I know enough about other non Christian religions to know that I would never seek them out and as I stated previously, the LDS Church is at the pinnacle of Christianity; no need or reason to fall back on other denominations because in this scenario, they have no salvic value (of course they have some good morals etc.).
So if God exists and He wants us to worship Him, it really is the LDS Church and none else for me. One could say this line of reasoning comes about because I accept the LDS Church's claim that it is the only true and God authorized Church on the earth.
I might follow Buddhism, but not devoutly just some of it. I like the way they try to connect with nature and use a peaceful attitude towards everything. Even if you didn't believe in the actual religion the principles are great for life.