Just came across these New Old Stock (NOS) Indy NVRAM, DS1386-8K-150. Have ordered a couple, hopefully they will be ok, not so sure about old stock though - if the battery is any good. After reading the semiconductor data sheet for the DS1386-8K-150, it seems that the battery is disconnected whilst in storage (bit 7):
TIME OF DAY REGISTERShttp://www.ebay.com.au/itm/250985368732?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
When set to logic 0, EOSC (Bit 7) enables the Real Time Clock oscillator. This bit is set to logic 1 as
shipped from Dallas Semiconductor to prevent lithium energy consumption during storage and shipment
(DIP Module only).