Another Set Back (very Frustrated)
You should step back here a little, Tell us what happened to the first cam? Wipe out a lobe or did the bearing surface go out?
If the rocker arms are getting oil, than at least two cam bearings are getting oil.
To answer your question about the cam bushings, the engine would have to be apart, you can run a rod thru the hole on the main bearing up to the cam bearing or just use a flashlight and make sure there is light from the mains to the cam bushings.
You could cut the oil filter open and see if there are any metal filings in the filter media.
If you had a pushrod or rocker arm problem it should be missing all the time.