Heavy 10 spindle bearing types

Hello everyone, new to the forum and new to lathe ownership. I am in the process of doing a full restoration on my 1940 10L. In my restoration book, the spindle has bronze bearings, with bearing caps that have felt + expanders in them. Mine has plain iron bearing caps, with no bronze spindle bearings. Does anyone know when the changeover to the bronze bearing happened? I've searched all over online, and have come across a few photos that have the same setup as mine. Additionally, I was wondering if anyone has had success with fixing a missing bull gear tooth by installing set screws in its place, and filing them to fit. (Maybe a zap with the welder between each screw for more strength?) Apologies in advance for any improper terms, still a beginner with machinery. Loving every second of the restoration though! Thank you.

The bearings changed in the late '40s - don't know the exact date.

People have built up bull gear missing teeth with either braze or a proper CI rod (nickel based) and shaped the tooth profile back. Do NOT use a regular welding rod - it will result in an extremely brittle repair. Set screws are VERY hard and are not a good idea for the rest of the gear train.

Thank you very much for the information and advice. I'll be sure to use the correct rod, now knowing regular rod will result in a poor repair.