No, the concentrations of either 1st PCR products or 2nd PCR products (Library PCR) do not correlate with the cell number output. In particular, high DNA concentrations do not indicate high cell numbers, and low DNA concentrations do not represent low cell numbers.
Very high DNA concentrations after the 1st PCR may be indicative of low emulsion stability, which resulted in the PCR reaction taking place in bulk (after excessive drop merging) instead of on a per-drop basis. The cell throughput in such a case will be impacted and likely lower than product specifications. High DNA concentrations, in that case, can lead to low cell numbers.