Here's a Link to The CFR 46 with the various requirements for licenses.
There's a chapter for Military sea time 10.213
2002 CFR Title 46, Volume 1
I also, don't believe a sail endorsement is attached to an OUPV,
I have a sail endorsement attached to my 100 ton Masters License, and it required credible service aboard sailing vessels, and a test.
You can take a sail endorsement class at places like Sea School and take their exam, get a certificate and document your time.