Montgomery County Democrats tend to like their politicians blow-dried and buttoned-down. Leon G. Billings is out to change all that.

The blunt-spoken Montana native has tried a number of imaginative ploys to draw attention to his underdog campaign for a seat in Congress. He flew his 90-year-old grandmother in from Zenith, Wash., to open his campaign headquarters in Wheaton, pointedly asked his rivals to limit their campaign spending and fired off a tongue-in-cheek statement decrying discrimination against left-handed persons.

And though he was the only Democrat brave enough to wear cowboy boots with a tuxedo at the party's annual Spring Ball this year, supporters say there is more to Billings than bucolic bravado.

They cite his firsthand knowledge of the workings of Congress, gained in a 20-year career that began when Billings became staff director for the Senate subcommittee on environmental pollution. In the late 1960s and early 1970s, the Senate panel spearheaded passage of landmark legislation on air and water pollution controls.

Billings, 48, later served as an administrative assistant to then-senator Edmund S. Muskie of Maine, moving to the State Department in 1980 when Muskie was appointed secretary of state by President Carter.

In 1981, Billings started his own consulting firm and has since represented corporate clients and municipal governments before Congress and a variety of executive agencies.

Because he trails some of the other candidates in fund raising and name recognition among voters, Billings made the calculated decision to distance himself from the pack. He has attempted that by launching the most spirited attacks on the Reagan administration and by making a few statements his rivals may believe were best left unsaid.

For instance, Billings has repeatedly decried the presence of John E. Boehm, a follower of political extremist Lyndon LaRouche, in the Democratic primary, calling Boehm "the kook factor" in the race.

Billings also is the only candidate who has released income tax returns for the last two years and a detailed list of large and small contributors to his campaign. However, his call for voluntary limits on primary campaign spending failed after representatives for candidates Stewart Bainum Jr. and Wendell Holloway rejected the idea.

Billings is tapping a network of friends in Washington and associates of his wife, Patricia, a longtime party activist, for volunteers and money. Those efforts paid one dividend last week when the League of Conservation Voters, the largest environmental political action committee in the country, endorsed Billings and gave him $500.

Bainum, who also has a considerable record on environmental issues, had campaigned hard for the same endorsement.

It remains unclear whether Billings' tactics for promoting his campaign will succeed against the better-financed efforts of Bainum or dent the formidable reputation Esther Gelman enjoys in Montgomery. But with 12 weeks to go before primary day, Billings is certain to have fun trying.