While the congressional candidates in Montgomery County's 8th District are in their hotly-contested Campaign as fast as they can raise it, Rep. Gladys Noon Spellman (D-Md.), in the adjoining 5th District, will have nearly $40,000 left over when the polls close Tuesday.

Spellman will be able to bank the money because her opponent, Republican Saul J. Harris, was the least successful congressional hopeful in getting and spending money. Harris reported to the Federal Election Commission that he had raised $6,560 and spent $5,806 as of Oct. 23.

The biggest spender in congressional faces in Maryland, however, another incubent with a little-known opponent, Rep. Robert E. Bauman (R-Md.), a darling of conservatives throughout the nation, collected nearly $190,000 for his contest, against Democrat Joseph D. Quinn, a certified public accountant from Denton, had raised and spent about $73,000, as of Oct. 23.

In the Montgomery County race, incumbent Rep. Newton I. Steers (R-Md.) and Democrat Michael Barnes are matching each other brochure-for-brochure, commercial-for-commercial, as they fight to the wire. Barnes had raised $109,512 as of Tuesday, while Steers had collected $105,384, according to members of their staffs.

In the 4th District, Rep. Marjorie S. Holt (R-Md.) also is expected to have some money left over from her race against Democrat Sue Ward.

According to reports filed this week with the Federal Election Commission, Holt had raised $104,618 and spent 82,877 as of Oct. 23. Her campaign manager said he hoped to use some of the excess money to buy bumper stickers and other supplies for her 1980 campaign, as a hedge against inflation. Ward had raised $29,745 and spent 27,375, according to the FEC reports.

The Spellman war chest was built up, he said, in case it was needed to combat last-minute advertising blitz, but Harra apparently has neither the resources nor the inclination to lauch such a blitz.

The conservative Americans for Constitutional Action released a report contending that Spellman has received $35,850 from labor organizations. Spellman headquarters puts that figure closer to $25,000, but concedes the figures vary, depending on what organizations are defined as labor.

On the other hand, the ACA placed labor backing for Barnes at $11,450, while Barnes' own figures show he has received more than $25,000 from labor unions.

Some of the problems results from the names adopted by organizations designed to funnel money to political candidates.

For example, the Constructive Congress Committee is the political action arm of the National Association of Electric Companies; the Democratic-Republican-Independent Voters Education Committee (DRIVE) is the Teamsters Union political fund; People's Public Affairs Committee is the Tobacco Institute Inc., and the Legislative Improvement Committee is the Carpenters and Joiners of America.