The National Football League Players Association scored what it called a major triumph yesterday in its efforts to pry financial information from National Football League clubs. The National Labor Relations Board general counsel ruled the NFL over the last five years has illegally withheld data pertaining to players' salaries and other player costs.

William Lubbers, the NLRB general counsel, informed the NFLPA and the league that a complaint will be filed against the clubs and the NFL Management Council for "unlawfully refusing to provide bargaining information" to the union.

The league now has the option of providing the NFLPA with that information or requesting a hearing before an administrative law judge.

Jack Donlan, the management council's executive director, said he interpreted Lubbers' decision "as putting to bed once and for all that it (the NFLPA) is not going to get our revenue figures. We've been telling them that and the board once again confirmed our position."

Donlan said he was basing his opinion on the fact that Lubbers will allow the NFLPA access to league television contracts for the last five years, but that all figures in the contracts will be deleted. Lubbers also denied an NFLPA request that it be provided with figures to show what percentage of the league's gross revenues is spent on players.

"If Donlan thinks this is a triumph for him, then why have they fought us for 18 months over obtaining what we wanted?" asked Ed Garvey, the NFLPA executive director who is negotiating a new collective bargaining agreement in which the union is asking for a percentage of the NFL's annual gross revenues.

"We asked for 15 items and the board ruled we should get 14. We already know the TV figures, but it will help to see the contracts. And the board said that with the figures we are now getting, we will be able to determine on our own what percentage of the revenues are going to player costs.

"That's a correct assumption. They've been giving us bits and pieces of information from 1980 and the board ruled that such information was insufficient. Now we can determine how much of that gross is really going right now to the players. Is it 30 percent, like we say, or is it 44 percent, like they want us to believe?"

Asked why he thought Garvey was hailing the decision as a victory, Donlan replied, "In my opinion, he is trying to bury the (John) Riggins decision. I mean, the board said they are going to get wage information but no revenue information. Garvey has been saying for weeks he can't get specific without revenue information, so how does this help him?"

Under Lubbers' ruling, the NFLPA would have access to: all television and radio contracts, including network and local arrangements, for the last five years; all standard player contracts the last five years; all incentive bonuses paid to players the last five years; a cost breakdown for injury protection benefits, termination pay and moving and travel benefits, and an itemization by each club of the monies paid for workman's compensation and any other financial benefits to players.

The two sides are scheduled to hold negotiating sessions Monday and Tuesday in New York on non-economic matters. Garvey said "we will know by Tuesday whether they will give us the information or not. If they don't, we have been directed to let the NLRB know and they will take it from there."

In another matter, Lubbers issued a complaint against Gene Klein, owner of the San Diego Chargers, for interferring in the union's attempt last season to collect late dues from quarterback Dan Fouts. The dues eventually were paid by San Diego fans.