Those of us who were playing pop/top 40 stuff back in them days(and who dare to admit it) remember that for a number of years, the organ was a standard fixture in most club bands, and in much, if not most recorded stuff.

Listen again to "Sugar, Sugar" The vibes are doubling that lick with the organ, which is also all over the bottom. And listen to "Yummy, Yummy, Yummy" again, it doesn't stand out, though it is more obvious in the last verse. As the young folks say, "It's in the mix."

And check the picture of the band. Their organ player was one of the most famous cartoon characters of all time:-)
The Archies

And hey, I am not trying to be a jerk about this stuff--it's music that I listened to and played long ago, and I am just trying to share what I know about it, for what it's worth :-)