Factory mascot is a term generally attributed to ornaments fitted as standard by manufacturers of a particular vehicle, or a mascot approved by them and sold through their agents. In this latter case the mascot would then be fitted by the vehicles owner but still classed as a factory mascot.
After they had approached and commissioned independent designers and sculptors, manufactures often used a third party maker to produced these ornaments. Most sculptors wanted to work in bronze, however the manufactures generally thought using such an expensive metal was a waste of money, especially as the bronze would be plated with either nickel or chrome.
Some manufacturers relented slightly and did allow the use of brass but generally zinc, pewter or polished aluminium were used. In some cases the sculptors did get their way and the more generous manufacturers occasionally allowed bronze to be used!