old (OEM from 1974) oilite bush (upper) and newer A/N standard, extended (shown below) from Clubman Racing
There is no porosity visible on either modern bush. Clearly visible on the original.
Begs the question, what is the material?
What is the source? You say clubman?
I have long ago learned that in ordering parts from ANY vendor, if you want specifically "original" AN, you MUST say and insist and verify what you get. Almost all AN dealers obtain alternate parts and will slip them in.
Since AN sells directly to bike owners, it is good for parts authenticity, but then AN also undercuts their own dealer network. American prices generally are almost double the UK prices.
Parts I get that are junk, including AN stuff dating back to the late 80's, get posted on my "wall of shame".
While the more recent ANIL, Joe seems to be trying, but perfection and truth are sometime elusive with all vendors.
I have used and continue to use all the British sources based on just under 30 years experience with them all.
IIRC in the US you could not buy direct from AN Shenstone or later BSA/Regal.
I did get stuff from Norvil and would, on ocassion, specify "genuine" AN and that is what I would get...I don't bother any more.