Hey Steve,
I think you are correct about them being older. I would think they look pretty much like what Sierra produced in the 1970s and maybe even the 1960s. I'm sure you know they should be perfectly fine to shoot. It says they are bench rest hollow points, and I would expect them to shoot real well even if they are not boat-tails.
If I remember correctly, these benchrest bullets were the predecessors to the Sierra MatchKings which came later in the late 1970s or 1980s. As far as I know, all MatchKing bullets are boat-tail hollowpoints. While some sources state that MatchKing bullets are not suited for hunting, I know quite a few folks who use them quite successfully for long range hunting of deer, elk, and even moose (not in .224 of course).
Unless they had some collector value which is more than the current price of Sierra MatchKing bullets, I would simply shoot them and enjoy the ride.
Best wishes,
Dave Wile