The D.C. Armory Board, operator of RFK Stadium, will be asked by New York investors to vote Friday on a proposed memorandum of agreement for the rental of RFK by a Washington major league baseball team.

Armory Board members, their staff and lawyers met yesterday morning with Emil Bernard, a New York investment counselor who heads a group wanting to buy the San Francisco Giants and move them to Washington.

Stadium and Armory general manager Bob Sigholtz and some staff members continued negotiations with Bernard and attorney, Richard Tinkham of Indianapolis, throughout the afternoon. They were reported to be in agreement about the rental package the Armory Board will review Friday.

Sigholtz could not be contacted last night for an assessment of the proposal's chances for approval, but others appeared to be optimistic that the Board would favor it.

During a break between negotiating sessions, Bernard and Tinkham said that securing a stadium lease was crucial to Bernard's plans to buy the National League Giants and move them here, possibly by April.

The realization of Bernard's plans would rest on league approval, a clean break of the Giants' current contract with Candlestick Park in San Francisco and the agreement of the club's current owners to sell.

Bob Lurie, a San Francisco financier, and Bud Herseth, an Arizona cattleman, bought the Giants two years ago for $4 million each in an 11th-hour sale to keep the Giants from moving to Toronto.

Competition from Charles O. Finley's Oakland A's across the Bay from the Giants has kept attendance and revenue down (the Giants have lost more than $2 million the last two seasons). Now Herseth wants out.

"I'd just as soon get out, I'm a meat packer and a cattle rancher and haven't had much time to devote to baseball," Herseth said yesterday. "If you can't enjoy the game, why stay in?"

Herseth said he has authorized Tinkham to find him a buyer and that Tinkham's option to buy half the Giants' stock runs through Jan. 15.

Tinkham said yesterday he is prepared, on behalf of Bernard and his co-investors, to offer Herseth $5.5 million for Herseth's half-share in the Giants. In all, Bernard's group is prepared to pay $11 million for the Giants with the money to be split between Lurie and Herseth, Tinkham said.

They are also budgeting another $2 million for player development and about $4 million for capital improvements to RFK Stadium. Bernard will not reveal the identity of his prospective partners, except to say one is Rocky Aoki, president of the Benihana Japanese steak house restaurant chain.

Bernard also has begun negotiations with WDCA-TV-20 here for the telecast of 81 away games and with WMAL radio for all games.

Lurie and Herseth's partner-ship agreement is a "buy-sell" one and conversations with the two yesterday indicated they have different interpretations of their pact.

Lurie, repeating his vow that the Giants will not be moved from San Francisco, said Herseth must give him 30 days to meet any offer made by a third party. "I either buy him out or he sells to the third party and I have a new partner," Lurie said.

But Herseth said Lurie either has to meet a third party's offer to Herseth "or sell (Lurie's half) to me." In this case, Herseth said, if Bernard offers him $5.5 million and Lurie doesn't match it within 30 days, he could buy out Lurie with Bernard's $11 million to be split between him and Lurie.

Bernard's optimism about buying the Giants is tied to his belief that neither Lurie nor any other major investor in the San Francisco area would plow that kind of money into the Giants, especially with the A's situation still in legal limbo.

Finley sold his club to Denver millionaire Marvin Davis, but the sale and transfer had been held up by a restraining order. The court lifted the restraining order last week after all the parties involved in the sale agreed, it would not be completed without the approval of the Oakland Coliseum management.

Bill Cunningham, the Coliseum's general manager, said yesterday that stadium officials, as well as the city and county governments voted yesterday morning not to release the A's from the 10 years remaining on their contract.

"The next step, as far as we're concerned," said Cunningham, "is preparing for the A's opener on April 10 - in Oakland."