The Playgirl magazine that Edith is looking at is the September 1976 issue (Vol. III, No. 4) with Jim Lampier on the cover.
This marks the first appearance of Liz Torres as Teresa Betancourt.
Liz Torres and Sally Struthers go on to appear on Gilmore Girls together.
Archie's continuing ignorance regarding blood types and race was first discussed in Season 1's "Archie Gives Blood."