Kodak B10 plates

I got a job lot of 6.5x9cm plates the other day. 4 boxes of a variety of Ilford plates, which I identified pretty readily including speeds (in H&D :-D ). There are 2 boxes of kodak plates though, marked 'B10' and 'photoscript' about which I can find literally zero information anywhere. Anyone any idea? Panchromatic/Ortho? Rough date? Speed? I'll probably end up throwing a few through a camera at the typical 6/12/24 or something to see but a ballpark start figure would be good.