More than 100,000 people are likely to congregate today on the peaceful middle-class towns of Lexington and Concord, starting as early as midnight, to watch to series of reenactments and speeches having to do with more momentous but less closely watched and planned events of 200 years ago.

The occasion is the commemoration of the opening battles of the American Revolutionary War--and the people of Boston, Lexington and Concord are ready for it.

Yesterday the two towns were decked out with American flags and banners hanging from every conceivable cornice, and bicentennial happy residents walked around in tricorner caps and ruffled skirts.

The throngs hadn't arrived yet but the local and national press was there in tremendous force, getting credentials and staking out the area for today's events.

The bicentennial is a tightly organized production, geared toward massive press coverage--in the atmosphere of efficiency and bureaucracy that prevailed in Concord and Lexington yesterday, the men in tricorner hats looked no more a part of the scene than they would have on any other day.

So whether or not the bicentennial evokes any sort of noble American past it is almost sure to give the masses what they want--a show. President Ford is in town--he spoke at Old North Church last night while protestors demonstrated outside--and he will declaim patriotic sentiments from the Concord bridge this morning.

Various bicentennial committees will carefully replay the key events of April 19, 1775, and parade about until mid-day. Most people there will probably miss some of the action because of the crowds.

There is even a touch of protest in today's events--the people's Bicentennial Commission, which says it wants to reclaim America from Wall Street, will be holding an all-night vigil in Concord while its parade permit lasts, in a celebration designed to call forth the harsh, indominable revolutionary spirit.

It's hard to tell if the People's Commission's effect will be more or less successful than the official cities' ones; from the looks of Lexington and Concord yesterday, the spirit abroad in the land was strictly 1970s.