Geoff… round headlight Studebaker Avantis had front fender turn signal housings molded integral with the fender…. The inner & outer lenses were the only parts removable from the fender…. Later ‘square light’ Avantis used a completely different turn signal unit, self contained, which was larger than the integral type, and simply clipped into the front fender leading edge opening with small ‘L’ shaped brackets…. In my opinion this later turn signal assy would be your best bet to accomplish what you are considering doing…. Ed