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You may wish to start your search with this article from Fortwiki:
While the area was supposed to get one of the largest weapons in the US Army’s coast defense artillery arsenal (16-inch Navy guns, like those that armed battleships), the site that was designated Battery 128 was completed without weapons in 1943, as it was clear by that date that the Japanese did not pose a threat to the area. Earlier in the war, a smaller gun battery, named Battery 155 Bolsa Chica, was located on the site. Simple concrete pivot bases, called Panama mounts mounted two World War I era 155mm guns called GPF (short for the original French title for Canon de 155 Grande Puissance Filoux mle 1917). This battery was active until 1944, when it was replaced by a modern 6-inch gun battery called Battery 242. Battery 242 remained active until 1948. The site also housed various structures that included a radar installation.
According to the Fortwiki article, only the Panama mounts of Battery 155 Bolsa Chica remain on the site of the original wartime batteries. The article also has helpful links that can provide even more information.
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Thank you! This is most useful!