In the '80/'90's, I have seen a locksmith make a handful of Chrysler keys (single sided), ignition and trunk, on several vehicles (lost keys) using a new key blank, a file and a tad of smoke (from a cigar lighter) averaging about a cut key every 30-40 seconds (and key works that lock just fine). He would then take the "filed" keys to make duplicates in his van, afterwards.
You could watch him with amazement figuring out exactly how he did/does it (i still don't have a clue) but it is a method used in video above.
He also said he can break into a car faster using his new key blank, file, smoke method then trying any other method (clothes hanger, metal tools down the glass, and so on) and after seeing him do it, I believe him.
It said the double sided keys take about twice as long do make.
The way I've always done it is to remove the back seat. Take a small flat screwdriver that has a 4 foot (1.25 meter) reach, and a flashlight. Take the screwdriver into the latch and turn counter-clockwise and the trunk will open right up. Then take the latch off then lock cylinder.
From there you can replace with a new lock cylinder, take existing lock cylinder to a locksmith to get new keys made or to get re-keyed to new lock pin set.
BudW