Every year, federal employes and members of the military give millions of dollars to home town charities here via the Combined Federal Campaign.

Sometimes, unions and individuals have tried to organize boycotts of the campaign because they didn't like participating groups, or because they hoped to embarrass the administration.

In some instances, the boycotters were protesting strong-arm tactics of bosses trying to meet dollar goals.

And from time to time, one got the impression that the boycotters were just looking for a reason not to give.

Now comes a letter writer who contends that by being generous during charity campaigns, federal employes may be giving ammunition to those who contend that U.S. workers are overpaid:

*"Several of your Monday Morning Quarterbacks have said they plan to take out their frustrations over pay and pension freezes by rejecting fund-raising appeals from political parties. As a fed, I don't often receive such requests, but every year I am solicited by the CFC.

"This program, in a conspicious way, shows the inherent generosity of federal workers. Up to now, I have always felt proud to be a part of it.

"However, since the Grace Commission [President Reagan's private sector survey on cost control] started looking for indicators that federal workers are overpaid, I suspect that the CFC accomplishments have been doing feds a lot of harm in return for their generosity.

"Maybe some others noticed it, too, because this year my agency failed to meet its goal and extended the campaign for a month.

"Perhaps trimming back on publicized charity would be an appropriate way to make a statement. If we get a pay cut -- and a pay freeze is a cut because of inflation -- feds need to adjust to live within their means.

"Secondly, to keep the Grace Commission and others from drawing wrong conclusions about our disposable income, charity might better be dispensed on a more personal basis. This has always been possible . . . . It is just a matter of multiple donations rather than the easier CFC check. Recent efforts like African relief, the Mexican earthquake and farm aid . . . offer more opportunities to make charity dollars count. So why should the fed shoot himself in the foot and give at the office?" -- C.D.B., Fairfax

*" . . . Regarding pay and pension freezes . . . it is fundamentally wrong to balance the budget on the backs of federal retirees.

"As a retired Foreign Service officer, I, too, have felt the pinch . . . . I support fair treatment for employees and retirees.

"And I liked the suggestion of one reader that political contributions be given to the National Association of Retired Federal Employees, of which I am a member.

"Imagine, therefore, my distress when I read the March 3 letter to the Monday Morning Quarterback [from a former federal personnel officer] that ended with a blast . . . against 'civil servants' bleatings, as pumped up by their unions.'

"Unfortunately, [the letter writer's initials] are my initials, too. I also have lived in Bethesda and my last Washington assignment was as a federal personnel officer. Since I have already gotten a few (so far, good-natured) calls . . . please tell your readers that Bill Shepard, who is running for Congress in Maryland's 8th District, emphatically disagrees with the views expressed by 'W.S.S., Bethesda.' " -- Bill Shepard