ET777

Hello. This is my first post here in the forum. Earlier today, I purchased a 1982 Precision Bass Special in walnut, from an online dealer. I will receive the bass sometime next week. I did research and have found that these are fairly rare basses. This bass appears to be in all original very good/excellent condition. However what has me curious is this very large half moon shaped hi-mass brass bridge. Its engraved "Fender pat. pending" and appears to be original to this bass. Does anyone have any info on this bridge? I searched up and down the web for info on it but came up empty. The only other one that Ive found is on a current listing from Japan on ebay for a 1982 in Alpine white, which has this bridge, although that one is pretty beaten up. Any insight on this? Was this a prototype bridge only in limited production? Thanks in advance. Photo of the body of the bass I bought in walnut, and the alpine white one in Japan below.