Exactly. Faber could probably kick his ass. That aint saying much. Lee was probably mostly hype.
It's quite useless to speculate in such a manner, since things like that are impossible to know.
Urijah wasn't even born when Bruce was in his prime.
If Urijah would challenge Bruce today, Bruce would have been 72 years of age.
If Bruce was born in the 1980's instead of in 1940, he would not have been the same person, and would probably have trained differently if at all.