On March 21, 2004, approximately 1415 Pacific standard time, a Cessna 172E, N3950S, registered to and operated by a private pilot as a 14 CFR Part 91 personal flight, nosed over during the landing roll at Willapa Harbor Airport, Raymond, Washington. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft was substantially damaged and the private pilot and his passenger were not injured. The flight originated from McMinnville, Oregon, about 1300. During a telephone interview and subsequent written statement, the pilot reported that he had just purchased this aircraft. The majority of his flight time was in an Ercoupe. During the landing roll, the aircraft drifted slightly to the right side of runway centerline. Being accustomed to the Ercoupe that has its brake positioned on the right rudder pedal, he mistakenly applied more right rudder/brake pressure than the left side, and the aircraft veered to the right and traveled off the runway surface onto soft wet grassy terrain. As the aircraft slowed, the nose wheel dug in and the aircraft nosed over, coming to rest inverted.