MARK ROLLISON must feel a little like the new kid on he block who has walked off with all the marbles - a big victory in his first major assignment since opening the Washington office for Dykema. Gossett, Spencer, Goodnow & Trigg, the largest law firm in Michigan.

In typical Washington fashion, politics - international in this case - played at least as big a part in the final decision as legal skills.

The client was Daedalus Enterprises Inc. of Ann Arbor, Mich., which wanted to sell $2.8 million worth of remote sensing equipment to the People's Republic of China to be used in a hunt for oil resources. The U.S. government, though, refused to license the sale on the grounds that the sensing equipment has potential military uses.

Rollinson, who joined the Michigan firm here this spring after leaving his own Washington firm, Rollinson & Schaumberg, did everything an experienced Washington lawyer does in a case like that.

He lobbyed the executive branch, even going into the White House to try to get the decision changed. He filed a suit in U.S. District Court here - all to no avail.

That is, until President Carter's national security advisor Zbigniew Brzezinski visited China last month. Before the visit Rollinson wasn't even sure whether Brzezinski intended to bring up with his Chinese hosts the withholding of Daedalus' export license - which was potentially damaging to the company and annoying to the Chinese, who already had technicians in Ann Arbor learning to use it.

Soon after Brzezinski returned, however, the word got out: the Carter administration had decided to allow the sale to go through as a part of the U.S. effort to expand relations with the People's Republic of China.

"It was a happy byproduct of Brzezinski's visit," said one expert in U.S.-China trade who is not connected with the Daedalus case.

"These decisions are made of rubber. We are all affected by the shifting tides of fortune," added another China trade expert who, although he had nothing to do with it, kept a close eye on Daedalus' fortunes to see what effect it might have on his business.

Which goes to show that sometimes it is as important to be lucky as it is to be good.

The Dykema firm, incidentally, is the first of Detroit's "Big Four" law firms to open a Washington branch. It is soon to be followed by Busnell, Gage & Reizen, who have made S. John Byington, former chairman of the Consumer Product Safety Commission, a full partner to open its Washington office.

Dykema's Washington branch is starting small, with one associate and two clerks helping Rollinson. Within five years, though Dykema expects to have 30 lawyers in Washington, both servicing its present Michigan clients and bringing in new business.

Now 52 years old, the firm has more than 100 lawyers (among them is Kathleen McCree Lewis, daughter of U.S. Solicitor General Wade McCree) and was described by Paul Trigg, the executive partner, as "kind of the S.S. Kresge of the legal business." That description doesn't mean that Dykema offers cut rates (it charges $35 an hour for an associate $135 for a top partner, the same as most large Detroit firms), but rather because it offers a department store's full variety of legal services.

H. Gordon Wood, the administrative partner (the firm is so big he spends 80 percent of his time running it, the rest practicing law), said Dykema decided to open a branch here because its partners were "constantly traveling" between Detroit and Washington. One partner was here regularly two days a week and he "had no place to hang his hat, no place to meet people."

Something to hide? David Webster, a partner in Williams & Connolly, won a $4.8 million damage claim on behalf of more than 1,200 youngsters who suffered emotional damage as a result of the bursting of a dam on Buffalo Creek, W.Va., in 1972.

Upon request, Webster sent a reporter a copy of the judge's order. Carefully inked out, though, were his legal fees.

It took one call to the clerk's office of the U.S. District Court in Charleston, W.Va, to find Webster was awarded 25 percent of the settlement - $1,188,541 - in legal fees plus $37,322.43 in expenses.

Webster followed in the footsteps of Gerald Stern, who while with Arnold & Porter won a $13.5 million settlement on behalf of 600 survivors from the same disaster. Stern and his firm collected a $3.5 million legal fee.

Former Vice President Spiro T. Agnew and two of his former associates - Jerome B. Wolff and I.H. (Bud) Hammerman - remained mute in a Washington's lawyer's office last week. They were there to give depositions in a taxpayers suit calling on Agnew and his former associates to pay back to the Maryland treasury any money Agnew may have gotten in kickbacks when he was governor. They were in the office from 9 a.m. to 3 p.m., but refused to answer questions put to them by David Scull, representing three Montgomery County taxpayers.

The American Bar Association has named a task force to study the ramification of the Supreme Court's decision in the Bakke case. Included in the group, headed by former solicitor general and Harvard Law School Dean Erwin N. Griswold, are Washington attorneys Brooksley E. Laudau, a partner in Arnold & Porter, and James N. Narbrit III, associate counsel of te NAACP Legal Defense and Education Fund.

Short takes: William M. Basking of Falls Church is president-elect of the Virginia State Bar Association . . Jane McGrew, partner in Steptoe & Johnson, succeeds Homer Moyer, formally of Covington & Burling and new deputy chief counsel of the Commerce Department, as president of the Washington Council of Lawyers . . . Jane N. Lamb, civil motions commissioner of D.C. Superior Court, elected new chairman of the Young Lawyers Section of the D.C. Bar.

Heard from two different lawyers, each of whom attributed it to a different Fortune 500 corporation head: "We had a good year. Earnings were six times legal fees."