what unit is used in factory front limited slip

[johnw893]

Last year I bbought a 69 chevy k10 that previous owners have butchered removing all the options that came on it pretth much. I know my truck originally came with limited slip in the front and rear because the build sheet says so but some idiot previous owner removed it from the front and installed an open dif. I've been trying to find out what would have been the original unit but havnt had a lot of luck. Any help would be appreciated.