You can't reliably tell the difference between a four-bolt and two-bolt main GM engine (like a small-block Chevy) without removing the oil pan or at least significantly disassembling the engine. The main cap bolt pattern is hidden completely under the pan. There's no external visual clue that would differentiate them. The engine casting number (1024388 in your case) might provide a clue if you cross-reference it with a GM engine identification chart, but that's not always conclusive as various internal components could be changed within the same casting number.
Therefore, you *must* consult a reliable GM parts catalog or a reputable online resource using the engine casting number to definitively determine the main bearing cap configuration.
