Tengah Type , the only Hunters at RNAS Brawdy in 1969 would have been a few T8s and some GA11s. The GA11 wasn't fitted with guns and the T8 had but a single gun which would have had to have been loaded manually rather than by fitting a gun pack.
Given the distance from Brawdy to the last known location of the C-130, an even earlier take-off time would have been required than from RAF Chivenor. Communications at Brawdy were rather primitive; even when I was there in 1975-6 the internal exchange was still manual - you had to lift the receiver and wait for Jones-the-phone to answer, then request the extension...
Fitting a loaded gun pack to a Chivenor Hunter simply wouldn't have been feasible in the time available.
I always thought that station call-outs in the early hours were fairly straightforward affairs. To cause true chaos, initiate the call-out at around 07:45 - 08:15! Or at 17:30 on a Friday. I once ran a Mineval at Wattisham; the first inject was a 'disaffected airman' who'd been 'blackmailed' to bring an IED into the COC in one of those scruffy little sports bag things everyone used (and which were never searched). But he was such a miserable sod that it took around 10 minutes before anyone noticed his unusual behaviour - I watched the resulting chaos with much amusement as the boltholing staff collided with people still responding to the call-out.