I don't doubt that at all.
Back in the late 70's, I tried my hand at planting some tomatoes. I
read up on them, and got six of the scrawniest plants you've ever seen
at the nursery. I planted right by the garage (white siding, west side,
full sun), watered, fertilized and staked them like the experts said,
and waited.
Then I started to get tomatoes. And more tomatoes. And more tomatoes.
I was getting an average of almost a dozen tomatoes off of these six
sick-looking sprouts every day! I couldn't eat them all. I couldn't
give them away to my families. My neighbors wouldn't talk to me... My
coworkers would run when they saw me carrying a brown bag... My clients
didn't (I was in hardware maintenance for IBM at the time) didn't want
to see me...
Yes, I can easily believe you got 120 lbs of tomatoes in your back yard!