3124 is the Cameo model designation - serial numbers are the sequential production number - VIN numbers include 'codes' for identifying the series [1/2T, 3/4T, etc] but not the specific model, and I've never heard Cameos were numbered differently

Bill

Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics