Shaws - per "Big Al" who used to frequent these parts a couple of years ago:
"They were all made in the same place. They all had a separate inked in number on the base plate in addition to the stamped patent number.
The first three digits will tell you the type. 137 is a neck pickup with less windings and 138 is a bridge pickup with a little more windings. There is a date code after the first three digits. 138 1280 would be a bridge Shaw made in December 1980. Not all of them had a silver “Patent applied For” sticker.
They had PAF coilforms with the square/round inspection holes and no T on top. The wire is a bright copper color (42AWG wire with a special polysol insolation buildup). The magnet was a special Alnico V that was longer like the 50's style and rough cast. This is a special magnet and the closest to a vintage PAF in tone to my ears. They had white plastic spacers and braided connecting wire.
They typically read under 8 Kohms and seem to average out in the middle 7's (7.2k neck zebra, 7.6k bridge double white). They sound very big and powerful in spite of the low readings."
So, I offer a very clean bridge (with the 138 prefix) for a neck version!!