Perhaps not rare, but uncommon yes. There were plenty of them made, but most people play with newer trucks.
I remember seeing one 29 Chevy truck in about a dozen truck shows I have been to in the past few years.
I have a 28 car, so I keep an eye open for the older ones at shows.
Can we see some pictures?
Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-