LSMs served mostly in the Pacific. Some served in Korea and later in Vietnam. Some were transferred to other countries' navy, including Australia and South Vietnam.
Go to NAVSOURCE for pics & histories of LSMs
http://www.navsource.org/archives/10/14/14idx.htm
The Revell large LSM kit represents the early version, all 20mm Oerlikon-armed. Later versions included a 40mm in the raised bow tub and a LSM(R) version. The LSM(R) sported a 5"/38 centerline in a decked-over well deck and a myriad of rocket launchers. The Revell kit has several sets of holes which need to be drilled out according to the instructions - leading to rumors of future versions in the pipeline.
I don't have the particulars, but other posts on the subject at the time the kit was released indicated that the M20 Greyhound and the M4 Sherman version included in the kit were not used in the Pacific where the LSM served.
Nautilus Models offers a new PE fret which includes railing stanchions, perforated cross-deck bridge, stern anchor racking, and yardarm imperovements. Mine is on order from Freetime Hobbies