What is the relationship between Gabriel and Noah in LDS/Mormon teaching?

In the summary of Noah on the lds.org site, it states that Joseph Smith taught that Noah is, in fact, the angel Gabriel. How exactly is this believed to have progressed? Did Noah exist as an angel first and then become a man? Or did Noah eventually become an angel? If he became an angel, does that mean he did not attain godhood? Is it a common believe that men become angels or angels become men?