Many of the 75mm f1.5 Biotar lenses sold in the US, or American occupied sectors of West Germany, don't carry the usual CZJ markings, so B 1.5 / 75 Jena, and a serial number may be all that's marked, but it is a T coated lens. There are other variations, such as AUS Jena.
It's also worth remembering that CZJ, Zeiss (West Germany), Schneider, etc, all dropped their coating symbols in the mid to late 1950s as all their lenses were coated.