My Series III has a flat front end which I'd like to return back to original. It still has the front panel win rad fan on the outside but another fan (modern higher power) on the engine side and I've got the lower apron and the grill and just bought the bonnet lock mechanism. Problem is I'm not sure how it works and my current bonnet doesn't have a pin, nor the bracket to fit one, so need to know how the bonnet release works. There are 2 clips on the top face which would seem to click over the pin but the release only releases the right hand pin (looking from the front of the truck) and the other doesnt move. Is this correct or is it defective as I have the option to send it back if its not right. There is a spring in the left clip but it can only be moved manually.
FFG

Sounds right. The pin is notched only on one side so the release only has to move one.

Thanks. I've seen the pins and I can see the catch hooks over the pin but what does the other catch do? My bonnet is currently held down wit 2 leather straps in the same position as the military catches, which i much prefer so may put these on, keep my original bonnet and get a hasp lock on the front panel.

The left one holds the right one open so that you can release the lever and use both hands to lift the bonnet.
On closing the disc on the pin hits the left one 1st and de latches the lock hook.
Just dismantled one to try and add extra security to it found the hole the left one pivotted on very worn and the peg on its rear bent and loose so it would not latch in the open position.

Just tried it and it doesnt hold the pin open but if I use the military locks I'll just put it on for completeness.