Oxygen Sensor(s) wiring 95 GMC K2500 5.7L TBI

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Service Engine light on when bought the old truck. O2 sensor (single wire) at exhause mnfld wire was cut and I’d like to find out where it is supposed to go, so it can be made whole. Repair manual says its a purple wire, but it also says they don’t show all possible year combinations. There is another O2 sensor just above the Catal. cnvtr that appears to be a 3 or 4 wire type. No post cat.con. sensors. Is it possible the 95 was some transition year, and they really only used the lower sensor, and plugged the manifold with a sensor and cut the wire? I can’t find any connector hanging loose. It has an ECM in glove cmpt, not PCM under hood, so OBDI, and single wire- single sensor, I thought?