With this date, this could be the round from the Winchester/Olin program that was tested the next year. These rounds were a duplex round that fired two slugs each shot from the same round, attempting to increase shock to the target. The programmed was ended in 1990, so the stamping is accurate.
If the round does not contain a duplex round, the yellow top could be a "Starburst" round, which can be used for spotting or a light incendiary. This round contained flecks of titanium which ignited and were thrown up to 10' upon striking a target. These rounds throw a bright shower of sparks in darkness and should be easy to identify.
Either way,these are expensive rounds.