As you can see in the bulletin, 1960 GM trucks changed to the low profile design Rochester "B" carburetor.
The throat changed to 2-5/8".
It has a bridge on top of the carburetor, that is threaded in the center for the threaded rod (both ends), that holds the air cleaner to the carburetor.
Before 1960, the throat was ~ 2-1/4". The truck air cleaner had a clamp to hold it to the carburetor.
So, from 1960 to 1962 the truck air cleaner construction was different than previous years.
I found this link:http://67-72chevytrucks.com/vboard/showthread.php?t=656098
Page down on the posting to find the 2 pictures of the black air cleaner. My guess is that this is the original for the 60-62 years.
I expect it would be hard to find.
Beginning 1963, the 6 cylinder engine line-up changed to 230/250/292.
I see GM dealer pictures of a low profile air cleaner (paper filter) with nozzle.
I also see GM dealer pictures of a large oil bath air cleaner that may be an option you could order.
The air cleaner design was probably continued on until the late 60's but I didn't look into it.
These air cleaners would fit the 1960 to 62 truck carburetors.