Members of a House of Delegates committee who threatened to kill a landmark savings and loan bill won a key concession tonight when legislative conferees agreed to a provision requiring additional disclosure of some withdrawals from state-chartered thrift associations last spring.

The concession, under which Maryland public officials would be required to disclose all deposit certificates they may have redeemed from the savings and loans on the eve of the thrift industry's crisis, was agreed to by six House and Senate conferees. It appeared to placate all but the most vociferous members of the pivotal House Economic Matters Committee, who staged a week-long revolt against their leadership to win a more stringent disclosure rule.

Only a few hours earlier, 16 delegates on the 24-member House panel -- sudden stars in a bizarre sideshow of General Assembly politics -- repudiated the conference committee's agreement on a measure that required only a limited number of public and private persons to disclose any large withdrawals that they made from savings and loans in the spring of 1985.

"What is sickening to me is that after all this General Assembly and committee have gone through in the past 12 months, we come down to this point where we look like we have something to hide," said Del. Gene Counihan (D-Montgomery), a member of the House panel who was leading the revolt against the chairman, Del. Frederick C. Rummage (D-Prince George's).

Rummage was part of a conference committee that signed a final agreement today on a massive bill to rehabilitate Maryland's savings and loan industry. At Rummage's insistence, the conferees approved a disclosure requirement more narrow than had been originally passed by the Senate.

There is considerable sentiment in the Senate and House that savings and loan depositors who were hurt by the industry crisis that began last May have a right to know whether individuals acted on inside information and escaped the S&L financial crash by withdrawing their money early.

Rummage defended the compromise language in a stormy session with his members this afternoon, begging them to abandon their demand for a more stringent disclosure requirement. The committee chairman said disclosure of "possible wrongdoing in the past is not properly a part of this regulatory bill."

"I'm going to implore you that yes, we need your support, vocal and otherwise," Rummage said. "It would be a catastrophe if the House of Delegates does not pass" the S&L reform bill.

Counihan and others said the omnibus S&L legislation was fatally flawed because it requires an official to disclose only those withdrawals made in the two months before the May crisis and that exceeded $10,000. Another section required possible public disclosure only if an official or private individual withdrew a deposit certificate of $100,000 or more. Investigations of such withdrawals would be conducted in secret under the bill.

"The net effect is to narrow the window of disclosure," Counihan said this afternoon. Counihan won promises from 15 committee colleagues to oppose the reform bill in its current form.

Del. Robert H. Kittleman (R-Howard) echoed Counihan, saying, "We're thinking what the people of Maryland are thinking. That is, they want to know . . . and purge the suspects."

Late today, Counihan and his committee allies met with Rummage and House Speaker Benjamin L. Cardin (D-Baltimore) in an attempt to reach yet another compromise on the disclosure rule. Afterward, Cardin said the committee members raised "legitimate concerns. We're going to try and address them."

The conference committee apparently did, agreeing to a new amendment that would require officials to disclose any certificates of deposit, regardless of size, that were withdrawn with an interest penalty from privately insured S&Ls last spring.

"It's going the whole nine yards," declared Del. Casper R. Taylor Jr. (D-Allegany), Rummage's vice chairman and fellow conferee.

Counihan said tonight he was still unhappy that the latest version fails to provide for disclosure of withdrawals of less than $100,000 by private individuals. But he added that the new amendment would "cast a much broader net."

Other committee members said they were less than satisfied. "What about the elected officials who notified other people with jumbo certificates?" said Del. Nathaniel T. Oaks (D-Baltimore). "That's where my problem is. Information could have been passed on. You don't have to have $100,000 to be a crook."

The House is expected to vote on the revised S&L bill on Saturday.