I believe Hi-Shocks were one of their earliest JHP designs, soon supplanted by the dated but still-serviceable Hydra-Shocks, and finally the HST (which are awesome, but hard to find.).
Honestly, I don't get too wrapped up in the exact bullet. Yes, I stocked up on HSTs when I had the chance, but the number one rule of gun fighting still applies: Have A Gun. If Hi-Shocks are what's available to you, take them and don't look back.