Monument to the Unknown Sailor

At first I thought it was a Navy-issue headstone for a sailor buried at sea. And honestly, though it might turn out to be something far less dramatic, that's still my best guess. Click on the photos to enlarge them.

An anchor is engraved near the dead center of the slab, but it sits a little crookedly, as if it was stamped into the cement by some primitive machine.

Also, the wording seems to be stenciled onto the slab almost haphazardly. It runs downhill, and all I can make out is "Bridgeville, PA," which is a town nearby. The characters seem distinctly military. Most of the words are long gone, which causes me to think that this stone has spent much of its life outdoors.

It's very hard to make out, but there seems to be some sort of serial number running along the left edge of the slab. Like the anchor, this number is "engraved" or stamped into the cement.

I've done a little research online and can't find a clear answer as to whether the military even issues--or ever issued--headstones for sea burials.

Alas, some long-forgotten great uncle of the Hickman clan perished in the Pacific Theater, or got exploded in his submarine during WWII. The dead sailor's brother inherited the stone eventually, along with the farmhouse. His wife didn't like the gloomy cement slab out among her flowerbeds, so when her own husband died, she packed it off to the attic. All earthly memory of one man's life, relegated to a corner of the attic, there to be shat upon by bats for a few decades. The widow-sister-in-law eventually sells the farm and moves into a nursing home. The farm is divided up and resold a few times. Who's going to take that stone out of the attic now?

Or maybe the Bridgeville Garden Club used to give these weird slabs to its members? Any thoughts?