Can any here explain the JHS designation?

[Quidnuncle]

I have looked and only seem to find that JHS is a milspec tubeprefix. I just received a sixpack of Sylvania 5814A's, triple mica, 1961 date code all matching. They had been advertised as CHS, which is Contractor grade or industrial grade.
As milspec ( if my assumption is correct ), I am thinking that I got an even better deal.

The other inconsistency is the numeric code of 015 , NOT the EIA code of 312 for Sylvania.
Could this be because these tubes were made for computer use?

I don't need as many of these tubes as I acquired, but have found them to be super-sweet in audio applications for their lo-microphonics and pleasant distortion at hi volume. I have found typical 12AU7's to be too mushy and quiet. These perform more like a premium 6072/12AY7 .

Thanks for any help!