To hear local savings and loan officials tell it, Mount Vernon Savings & Loan of Arlington was too much of a risk to acquire, even with financial assistance from the government. That's why they showed little interest in bidding for the financially troubled S&L.

But by spurning an offer to take over Mount Vernon, local S&Ls opened the door to further interstate competition.

Brooklyn's Metropolitan Savings Bank agreed to take over Mount Vernon, gaining entry into a market that's widely coveted by financial institutions outside metropolitan Washington. That makes the risk worth taking, implied a Metropolitan official.

He could be right. A combination of timing, financial muscle in the form of Metropolitan's $6 billion in assets and the strength of the Washington area market could render a silk purse from a sow's ear for Metropolitan.

Only time will tell who made the right decision.

Ironically, Metropolitan had no plans at all for this area until Mount Vernon was offered as a bonus by federal officials who were trying to put together a neat little package that would solve some of the thrift industry's lingering problems.

The Federal Savings and Loan Insurance Corp., the government insurer of S&Ls, sent out invitations for bids on Mount Vernon as early as February but found no takers among local institutions.

"We didn't make a bid on it because the numbers just didn't look right," said one Northern Virginia S&L official, referring to Mount Vernon's balance sheet.

Conversations with other S&L executives in the area indicate that most agreed that the FSLIC would have to guarantee them a cash infusion of $12 million to $20 million to take over Mount Vernon.

Two years ago, Mount Vernon was riding the crest of a go-go policy that established it as an aggressive lender and one of only three profitable S&Ls in the area. It was the height of the industry's worst financial crisis in four decades, but Mount Vernon seemed oblivious to it all. Ironically, as the industry began recovering, Mount Vernon fell on hard times.

December 1982 figures compiled by the Federal Home Loan Bank Board for all federally insured S&Ls showed that Mount Vernon's net worth was only $2.1 million. Net income had evaporated from a monthly profit of $100,000 in the first half of 1982 to minus $600,000 in the second half of the year and reserves were well below the accepted level.

Finding no takers in Virginia for the hemorrhaging Mount Vernon, the FSLIC turned to institutions outside the state. In the meantime, Metropolitan was seeking regulatory approval to acquire First City Federal Savings & Loan in Bradenton, Fla., in which it already held a 10 percent interest and options to buy up to 49 percent.

Presto. The Bank Board and the FSLIC had found the solution to their problems at Mount Vernon and First Florida Savings & Loan of Gainsville. Metropolitan could have First City Federal if it agreed to take the whole package. Included in the package offer was Middle Peninsula-Northern Neck Savings & Loan of Gloucester, Va., owned by Mount Vernon.

Obviously convinced that the potential outweighed the risks, Metropolitan agreed to take the package and form a subsidiary, First Florida Savings Bank, which will operate Mount Vernon.

With only one branch and a drawer full of problems, Mount Vernon held no attraction for other S&Ls in the market. Why, then would Metropolitan be interested?

"Our bank is such a size that what's required to straighten Mount Vernon out may not be as much a problem as it would be for a smaller bank," explained James Kerr, a vice president at Metropolitan.

What's most important in all of this, Kerr added, is that "we now have a presence in" Virginia.

"The proximity of Mount Vernon to the District of Columbia is important and basically, we wanted to achieve a presence there."

The transaction, which is similar to others engineered by the FSLIC, has been described as "cost-effective." Just how cost-effective is subject to speculation since neither federal officials nor Metropolitan will say how much of the public's money was used to sweeten the deal for Metropolitan.

What we have is a nice, neat little package that solves at least two of the FSLIC's problems and one that gives tacit approval to yet another advance in interstate banking.

And Metropolitan will either take its lumps and succeed, or it will have miscalculated.