Inputs required for Random Forest Regressor and ways to improve performance
A random forest trained on data whose labels are all positive integers cannot produce any prediction less than 1. So yes, the model will be less accurate.

I would suggest including a random subset of the rows with 0 sold, so that the forest can learn a (hopefully representative) pattern to them.  I'd also probably weight them higher in the fitting algorithm, to reproduce a more faithful average of items sold (in each leaf).