How to get into the trunk of a 65 Barracuda????

The aforementioned plug in spare tire well. The latch and the catch.
If there is no spare,you may be in luck. Long extension and remove bolts from trunk lid. Easiest by far.

For security panel, a couple putty knives 10” in from each side may release latches. But i doubt it1DCEB7D3-C01A-493B-A4AB-B4F1B2CDCB34.jpegBC78F3E4-A513-4DED-8E3E-27CD928FCEDC.jpegC3B73CFB-32FC-4CCF-895C-4FC3D1482767.jpeg