Delco Plugs FR2LS vs. 41602

[ZR1Trev]

I went to purchase plugs for my '91 and found that the stock AC FR2LS plugs that I used last time have been replaced with AC 41602. Does anyone know what the difference is?

My car is 100% stock and only driven 1K miles a year, so there is no need to upgrade to platinum or iridium replacements.

Thanks,

Trev