In a short, rather quick ,response here, no they did not. Most Vikings entered battle with a shield and sword, or axe, "berserker" or not. we can see reference to this, although not in a raid, but battle against another man, in Egil's Saga when it mentions he went to an island to fight a man named Ljot, who is referenced as a berserker earlier stating,

"Then he made him ready for the combat. He had shield and sword. Ljot was a man of vast size and strong. And as he came forward on the field to the ground of combat, a fit of Berserk fury seized him; he began to bellow hideously, and bit his shield… Ljot sprang swiftly to his feet."

W. C. Green, The Story of Egils Skallagrimsson: Being an Icelandic Family History of the Ninth and Tenth Centuries. Translated from the Icelandic by W.C. Green. London: E. Stock, 1893.

We also see reference to them carrying shields when talked about broadly in the Ynglinga Saga with,

"Odin could make his enemies in battle blind, or deaf, or terror-struck, and their weapons so blunt that they could no more but than a willow wand; on the other hand, his men rushed forwards without armour, were as mad as dogs or wolves, bit their shields, and were strong as bears or wild bulls, and killed people at a blow, but neither fire nor iron told upon themselves. These were called Berserker."

Snorri Sturluson, The Heimskringla. Translated by Samuel Laing. London, 1844.

While both original works are thought to be written by the same author, Snorri Sturluson, they are some of the best sources we have when looking at berserkers.

*I apologize for the short answer, I am currently at university, but wanted to get an answer to you in my short free time. The only issue I could see with the post right now is my citations, as I wrote them hastily for the aforementioned reason, and my grammar. Hope this answer helps.

Best Regards,

Viking_Norse