The election night advisory memo to the press was mailed more than two weeks ago from the campaign headquarters of Michael Barnes, Democratic candidate for Congress in Montgomery County. According to the memo and the attached diagram, every detail would be taken care of, down to the 16-inch high riser for televison cameras located 12 feet from the podium in the center room of the Versailles Suite of the Bethesda Holiday Inn.

Yesterday, at the campaign office of Barnes' opponent for the 8th Congressional District seat, the press aide to freshman Rep. Newton I. Steers (R-Md.) said, "Nah, we don't have any special plans, but of course you guys are welcome" to spend the night watching returns with Steers in his headquarters in a converted carpet store.

The difference in the planning for election night illustrates the sharp contrast between the respective candidates and their campaigns.

For Barnes, a fastidious, no-nonsense tax lawyer who acts older than his 35 years, planning for the party is merely the final step in his quest for office that began 18 months ago.

For Steers, a 61-year-old career legislator who has a rumpled appearance and a prep school, Ivy League upbringing, the casual approach to election night is consistent with his happazard campaign style.

But the differences between the candidates do not begin and end with style: there is considerable sustance on which they differ, and after an intense, occasionally acrimonious seven-week campaign, they go into the last 72 hours agreeing only that's it's any-one's ballgame.

Despite polls released in the last few days by three weekly newspapers in the district showing Steers leading by a substantial margin, Steers refuses to be complacent. The Montgomery County Sentinel gave Steers 32.6 percent, Barnes 25.7 percent; the Montgomery Journal showed Steers leading 45 to 34, and the Gaitherbury Gazette called it 42 to 20 for Steers.

Barnes' campaign manager Keith Haller, does not quarrel with the findings, but said yesterday that the large number of undecided voters reflected in each survey, between 21 and 30 percent, convinces him that "it's out there for us to win."

Haller's optimism is buoyed by the knowledge that Democrats outnumber Republicans nearly 2 to 1 in the district.

Steers also leads in the number of newspaper endorsements, having been tabbed for reelection by the Baltimore Sun, the Baltimore News-American, the Sentinel and the Gazett. The Journal took no position, saying Steers and Barnes offer voters "two good alternatives."

But Barnes last Sunday received the endorsement of The Washington Post, which he says will make the difference. Barnes is exploiting that endorsement in two new pieces of literature being distributed this weekend, and in a new television spot.

In a third new brochure, Barnes continues his relentless criticism of Steers voting record, including statements that earlier caused Steers to file a complaint with Fair Campaign Practices Committee.

"It resembles a smear sheet to us," Steers' press aide, Dave Blee, said last night.

Barnes characterizes Steers' performance in the 95th Congress as "almost totally ineffective," in which he "demonstrated that his basic judgment is subject to question and often unbefitting to a congressman from Montgomery County."

The latest brochure brought up new charges that Steers is a member of both the Metropolitan Glub and Chevy Chase Country Club which Barnes said "discriminate against women, against blacks and against Jews."

Steers responds to that statement by nothing that Barnes' father-in-law belongs to the name two clubs.

It is on the question of Steers voting record that the rhetoric becomes the most inflamed.

Barnes and Steers have been arguing for more than a year about where Steer stands on various hot issues, each citing a particular vote to make his point. In an exchange of accusations last month on how Steers really voted on congressional reform and nuclear power, Rep. Morris Udall (D-Ariz.) found himself caught in the middle.

Udall. in an effort to swing an endorsement to Barnes from the local chapter of Americans for Democratic Action (ADA) had allowed his names to be signed to a letter, prepared by Barnes, that attacked Steers on those two issues.

Shortly after the Udall letter was made public, Steers made it a part of his complaint to the Fair Campaign Practices Committee. Steers also called Udall and demanded a retraction.

Steers got the retraction from Udall, but the battle wasn't over. Barnes got back to Udall, and yeaterday an aide to the Tucson Democrat issued yet another statement that said the "clarification" he wouldn't call it a retraction - was "not to be construed in any way as lessening of Mo's strong support for Mike."

The statement concluded by saying that Udall "does not want to get into a debate between Mike and Steers on what votes are important or not."

But that has been the essence of the aggressive campaign carried on by Barnes.

Voters who are confused by the unmending exchange of charges can look to two issues that both candidates agree are important, and on which their views are opposite.

One is the Kemp-Roth tax bill, of which Steers is a co-sponsor and for which he voted. Steers contends that the plan, which would reduce federal income tax by 10 percent a year for three consecutive years, is an effective way to attack inflation. Barnes calls it "the No. 1 issue in the campaign. Its passage would have devastating consequences in Montgomery County."

Another issue on which their stand is easy to discern is tuition tax credits. Steers voted to give tax relief to parents of parochial and private elementary and secondary school children. Barnes opposed the credits, saying that in many instances they would go to support "white academies where the public school enrollment is largely block.