"The M1918 155mm howitzer also continued in service until late in the war. The point I wish to make is that this howitzer was in use by field artillerymen of the 11th Marine Regiment on Guadalcanal,"
The artillery regiments of both the 1st (11th Marines) and 2nd Marine Divisions (10th Marines) had 155mm howitzer battalions in 1942. But it doesn't appear that either battalion made it to Guadalcanal.
I suspect that 155mm M1918 howitzers on Guadalcanal belonged to Americal (221st FA Bn) or 25th Infantry Divisions (90th FA Bn).
Rottman's U S MARINE CORPS WORLD WAR II ORDER OF BATTLE says assets of 4th Battalion, 11th Marines (the 155mm howitzer battalion) was used to form 1st Corps Artillery Battalion in New Zealand on 11 Dec 1942.
Interestingly enough, Rottman has a second Army CA 155mm gun coast artillery unit deployed on Guadalcanal: "Battery B, 259th Coast Artillery Battalion - Deployed as Provisional Battery H, 3d Battalion, 244th Coast Artillery Regiment (155mm Gun) and was redesignated on 20 Jan 43"; and has it arriving BEFORE F/244th Coast Artillery Regiment.