73 850 factory chrome

i am working on a rebuild. its a 73 850 and there is a chrome rear swing arm and the front iso mount is chrome are those factory or a aftermarket add on have looked at tons of pics and havent seen any other ones with the chrome

No, swing arm and iso mount would not have been chromed from the factory.

There are plenty of sites that show vintage ads - these are probably the best source for accurate pictures of what the bikes looked like when they were new.

I like this site:
http://www.classicbike.biz/Norton/A_Link/Norton_A.htm

I,ve got that poster on my wall, Vivian was a good looking girl.
Engine mounts, swinging arm & frame black, Yokes & front disc silver.
There was a sticker somewhere on the frame, "For motorway use, a 21 tooth sprocket is recommended", I can remember it, but not where.
Wouldn't be on it now, as it is on it's 3rd frame :?