Dunno where that sarna date comes from, but the Nightstar entry in TRO 3058 doesn't say anything about any production prior to the Clan Invasion.
Since the original production facility was bombed in 2786 or 2787 you get 3036 or 3037 as the intoruction date if you take the "two hundred and fifty years would pass" in it's literal meaning. 3036 is impossible date for the NSR-9J since there is no gauss rifle, 3037 would theoretically be possible for NSR-9FC since all components are technically available (though ER PPC only in DC starting from 3037, and this is a 'mech from the enemy side). 9FC is also not described as low-tech variant, so my conclusion would be that both '36 and '37 are false, and the real date is '50-'55.
(Edit) Master unit list gives 3057 for both variants.
Edited by Gigaton, 30 March 2012 - 03:04 PM.