unidentified flat wounds

I have these great old flats on my T-40
I'm wondering what brand they may be? I have a feeling that they have
been on the bass for the past thirty or so years, the silk winding end is bright orange
or deep orange depending on your perspective.
any ideas?
I usually play flats but on other basses its D'Addarios which on those you can see the winding
these other ones on my T-40 are the smoothest flats I have ever encountered! You can't even
really see that there is a winding on them, really cool.