At the risk of being informed otherwise, it looks to me like a genuine, well cared for original from perhaps the mid to late 1940s. Your Omega is equipped with shock protection (Incabloc balance jewels). We often see this model of Omega movement not so equipped. The case was never, is not now, nor will it ever be water resistant. Competently and thoroughly serviced, and treated respectfully, this watch could give very good service, and be a pleasure for a long time. Ditch that strap, however.