Although the University of Oklahoma already has received and made public a letter charging its football program with 16 violations of NCAA rules, investigators have not yet finished their work, and new allegations may be forthcoming, The Dallas Morning News has learned.

Members of the NCAA enforcement staff are attempting to gather information concerning car financing and other extra benefits that may have been made available to Sooner players.Should those additional efforts turn up more allegations of infractions, said an NCAA spokesman, the official letter could be amended at any time - either before or after the school's representatives appear before the Committee on Infractions, which determines what, if any, penalties should be imposed.

In addition, sources have said that at least one infraction uncovered both at OU and rival Oklahoma State University centers on offers of cash or merchandise in 1985 for highly recruited receiver Hart Lee Dykes of Bay City, Texas.

Dykes, who signed with OSU in 1985 and has a year left in the Cowboys' program, has been granted immunity from eligibility penalties by the NCAA in exchange for information against his own school, said two persons close to the probe.

According to those sources, who asked to remain unnamed, Dykes has told NCAA investigators that Sooners receivers coach Mike Jones offered him $1,000 cash in an envelope just before the 1985 national signing day.

Jones and OU athletic director Donnie Duncan did not return several phone calls for comment on the allegation. Dykes also could not be reached.

At OSU, Dykes has charged that former OSU assistant coach Willie Anderson offered him an automobile as national signing date neared. Anderson, who now runs Integrity Management sports and talent agency in Stillwater, Okla., said he would have no comment on any allegation.

Both schools have received official letters of inquiry from the NCAA that list charges substantiated by investigators.

OU has released a five-page list of the 16 charges contained in its letter. The summary omitted all names of coaches and players.

OSU officials have confirmed receiving an NCAA letter but have refused to divulge its contents.

Both institutions are currently conducting internal investigations of the alleged NCAA infractions in advance of appearances before the Committee on Infractions. OSU athletic director Myron Roderick said the Cowboys' investigation should be completed by the end of September.

Already, the NCAA has charged that from fall 1983 through spring 1986, Sooner athletic department employees scalped season tickets for two players; operated a slush fund that padded staff salaries and bankrolled other violations; and provided some players and recruits with airline tickets, rental cars, free or discounted clothing and shoes.

During the three-year period in question, the Sooners recruited the majority of the players who have led the school to a 33-3 record and one national championship since 1985.