About 600 guerrillas of the Palestine Liberation Organization streamed out of a ferry at 3:30 a.m. today to the remnants of what earlier had been a vibrant celebration welcoming their arrival from West Beirut.

Several thousand determined but hoarse and red-eyed Palestinians, left over from a once-huge crowd, still managed a warm reception, joining the marching guerrillas in the chants about blood, sacrifice and victory that had sounded with a throatier enthusiasm 10 1/2 hours earlier when the welcomers first gathered on the docks of this ancient Mediterranean port.

The guerrillas who arrived this morning were the first of several thousand scheduled to come to Syria in the evacuation of PLO fighters and Syrian soldiers from Beirut.

Originally they were to have come to Syria in a bus convoy along the Beirut-to-Damascus highway, but use of that route has been postponed at least until Friday.

The postponement yesterday of an expected overland exodus and a decision to bring the guerrillas here by ferry caused a mad dash from Damascus to Tartus by PLO and Syrian officials, Palestinian supporters and reporters.

A large crowd began gathering at the port at 5 p.m. after it was announced that the boat would arrive at 6 p.m. But the Sol Georgios, the same ferry that took the first group of PLO fighters out of Beirut to Cyprus last Saturday, did not enter the harbor until a half hour after midnight. It docked and lowered its ramps three hours later.

During the long hours of waiting, groups of Palestinians and Syrians paraded on the docks.

They sang PLO songs, danced and jumped up and down for television cameras. The activity was as much to keep warm in the nighttime chill as to keep spirits high.

By 10 p.m., people were gathering burlap bags to lie on or wrap themselves in. The dock was suddenly reanimated when the ferry was sighted at 12:30 a.m.

Crowds pushed to the edge of the dock. Young girls waved bouquets of flowers. Pilot boats and a tug, whistles blowing, escorted the ferry to the dock.

Syrian Prime Minister Abdel Rauf Kasm, Defense Minister Mustafa Tlas and Khalid Fahoum, speaker of the Palestine National Council, waited with the crowd to welcome the guerrillas. Kasm gave a brief welcoming speech when, after the hours of expectation, the guerrillas finally trooped down the ramps of the ferry onto Syrian soil.