Our report on mislabeled tapes for ''Summer of '42'' and ''The Green Berets'' prompts new inquiries by the MPAA

You just can’t judge a video by the MPAA rating on its cover. First, we discovered a G rating mistakenly printed on the box of the occasionally violent, PG-rated version of Disney’s Treasure Island. Now we’ve found two more ratings errors on videos — and, in the process, prompted new inquiries by the MPAA.

Parents in the market for a sweet, relatively tame coming-of-age story for adolescents might be put off by the R that was accidentally put on the boxes of Summer of ’42 (Warner) that have been in video stores for nearly a decade. Produced in the stern early days of the rating system, the 1971 film was initially rated R but re-rated PG a year later — 12 years before videos went into circulation with the Rs on the box. Although Warner says correctly printed packaging has been produced, we found only the erroneous R ratings on boxes in several branches of the national video chains we checked. Meanwhile, all the cassettes in circulation for the G-rated John Wayne Vietnam flick The Green Berets (also Warner) read ”Not Rated.”

While acknowledging the misleading flubs, Warner declines to say if it plans to amend future printings of the Green Berets‘ packaging. But it may have little choice: The MPAA is investigating both cases, and it tends to be almost as conscientious about ratings as parents should be.