He doesn't have his piano yet, doesn't have his striped shirt, barely has any hair, his personality consists of blank stare, and can't even talk, but it's the same Schroeder who would later idolise Beethoven and fend off Lucy's advances.
Oh, how much this strip changed over the years. Most comic strips, those that were ever any good, start off great and trail off over the years, as the need to continue bringing in an income overrode any considerations of quality. Peanuts went the other way, starting off sharp but gaggy, then gaining profundity. Its characters changed so much since 1951, they're like different people. (I had to stop myself from saying "between then and now," it's hard to believe that Charles Schulz has been gone for over nine years.)