Hello OUTFXD,
I have a 46 Dodge Special Deluxe but a Canadian Model. I just went out and got a picture in hopes it helps. I am not sure your release set up would be the same as mine but it is all I can offer.
I can only think of two options as accessing the catch from below appears impossible. The photo orientation is the square hole is to the front of the grille. On the right side of the photo is the connection of the cable to the mechanism. If you have a small gap between the hood and the grille you may be able to insert a thin piece of steel, (Metal Ruler) and push the knob back towards the firewall at the appropriate angle. You would have to be right of the secondary latch and angled slightly from left to right to get the proper directional push. The connection between the catch and the wire is slightly recessed with a raised lip around it so you may have to bend the front edge of the flat bar down a bit. This idea only works if there is a bit of room between hood and grille.
The second option would be to create an L shaped piece of perhaps 1/4 or 3/8" round stock or ready rod with enough length to reach through the grille and up the hole of the mechanism from below. I am not sure you could get enough purchase on the round stock to push that mechanism back but you never know. Both of these require steady hands and patience, neither of which I have.
Best I can come up with and good luck. Dave