Silver Fox,
So! YOU ARE THE ONE WHO IS GOING TO WIN THAT LT DETECTOR! Good plan!

If the Land Star works on that beach, then all metal detectors probably will.
I owned a landstar when it first came out and as you know, it is a simplistic metal detector, nothing like the high end machines in the "near $1000.00 range"
Is Coney Island on the ocean or is it on a bay etc?
It is wet salt sand that a detector sees as a conductive target.
I guarantee you couldn't hunt Florida's wet salt sand with it, or any other single frequency unit, with any degree of success.
Hey, if it works, use it.
Just for a comparison though, a detector designed to work wet salt sand- say an Excalibur, will hit a nickle at about 10" deep. An MXT will nearly handle wet salt sand, but will only hit the nickle at 4-5"
1 good gold ring 3-5"" deeper than your LS will go, could pay for a detector designed to do the job properly [multi or dual frequency detectors]?
Here are 2 informative readings=
http://www.findmall.com/read.php?32,692963
http://www.tesoro.com/UnderwaterDetectors.html