Early in the war certain Seabee Battalions were attached to the marine corps. Each marine division organized prior to 1944 was allotted an engineer regiment which consisted of three battalions: a battalion of combat engineers, a battalion of pioneers and a battalion of Seabees. This arrangement was discontinued in February 1944.
The numbering procedure was such that the designation of a Seabee Detachment was usually a configuration of the designation of the battalion from which the detachment was drawn, thus, Detachments 1050 and 1051 were probably drawn from Mobile Construction Battalion TEN (MCB-10).
Peter Gillum of the Retired Naval Construction Forces Association maintains a directory of retired Seabees. You can reach him at < firstname.lastname@example.org >