The political organizations of the Greater Washington Labor Council yesterday announced their endorsements of State Sen. Charles Gilchrist for Montgomery County executive and Winfield M. Kelly Jr., the incumbent, for county executive in Prince George's County.

The endorsements were among 115 for Congress, the state legislature and county offices made by Montgomery and Prince George's Committees on Political Education (COPE).

The labor backing carries with it the tacit support of 20 union locals in the bicounty area. Prince George's has about 44,000 AFL-CIO union employes, while Montgomery's AFL-CIO membership numbers about 20,000.

However, according to Montgomery COPE chairman Mike Gildea, financial support from labor for primary races will be concentrated in the races where labor candidates are anticipated to have the most difficulty.

In Montgomery County, both Michael Barnes, a Democrat, and Newton Steers, the Republican incumbent, were endorsed for the 8th District Congressional primaries. Gladys Spellman, who represents the 5th District, and Sue Ward, a Democrat who is running in the 4th District also received COPE's backing. COPE passed over 4th District Rep. Marjorie Holt, a Republican.

In the Montgomery County state legislative races, the labor committee endorsed all incumbents except State Sen. James Clark (who also represents Howard County), State Sen. Lawrence Levitan, State Sen. Howard A. Denis and Del. Robert Jacques.

For the Montgomery County Council, three of the four incumbents seeking reelection won COPE's backing - Neal Potter, Esther Gelman and Jane Anne Moore. Elizabeth Scull, the opposed collective bargaining for public employes, was passed over. She is unopposed in the primary.

Also endorsed for the council race was Democrats Ruth Spector, Michael Gudis, Scott Fosler and Mable Granke. Only Spector is unopposed in the primary.

A total of 15 Democrats and 12 Republicans are vying for seven nominations in each party primary in Montgomery.