I have an early 80's M1A I am looking for a barrel number onit but can only find the marking Geneseo ILL  I have removed the handguard and there are no numbers anywhere.  Just took the handguard off my other early 80's M1A and there are no markings.  The serial numbers are 0189xx and 0190xx  just trying to determine if these barrels are USGI or commercial.  SA advised that all parts on these weapons should be USGI

any ideas?

Can you rephrase the question?  Is it that you have a barrel on an early 1980s M1A with only the Geneseo IL marking and you're looking to know its manufacturer?  Have you removed the hand guard?  Sometimes barrel markings are not visible by pulling the operating rod to the rear.  What is the contour profile of this barrel, standard, medium or heavy?

Are the barrels standard, medium or heavy contour?

I have a winchester USGI barrel that has all the numbers, and winchester script on the opposite side from normal. If it was on a rifle, you would need to remove the action from the stock to see the markings. This isnt common, but I have seen other USGI barrels that had the markings stamped 180 degrees from the correct location.  There is a chance your rifles were rebarreled at some time in there past with non gi, barrels.

Do you have a national match barrel?  Is it stamped with an NM up near the flash suppressor?  I have a late '70's M1A with a NM barrel and it is stamped with the same "Geneseo, IL on the bottom of the barrel.

I've been told they are commecial made match barrels.