Please help me identify a Strat Duncan pickup

[LieMfB]

I have this old SD Stratocaster pickup. No sticker, only a stamp on the back that says "SD 2 94".

Wires are cloth, seems wax-potted. Staggered poles. DC resistance is 6.3.

Anyone knows what pickup I have?

Bobbins and stamp (but not the wire) look like in this one:
http://i183.photobucket.com/albums/x153/stratman323/Misc/119_1934.jpg

Thanks for any help!