Been here for a little bit and trolled for a while and never found this done so heres my lame ass write up w/ crappy cell phone pics.
I originally had the ammo can mod with a can mounted on each forward corner. After a while I needed more space and started looking at truck boxes. Because of my bestop I couldnt do the cross bed ones and didnt feel like spending a bunch of money on a ss or aluminum box so I went w/ a contico tuff box from lowes (<$60). I've seen some mounted temporarily using straps or bungees but I wanted something more permanent so...
ATO rail nuts/slugs (I bought 8 previously but only need 2 for this project)
2 - 4" 3/8-16 bolts
4 - flat washers (gonna have to get a couple more though)
2 - spacers
2 - lock washer
1- contico tuff box
Marked and drilled holes through the rear of the box (my measurements put me right at 1" from the bottom of the outer lip/rim). I needed about 3.5" of standoff because of my top and the lid opening so I used lock washer and flat washer inside, 2 flat washers, spacer, then another washer (still have some space so may add more washers later to take it up). Tightened everything up and now mounted pretty securely.
Now the molle mod is something I did in my center console originally but also added to the Tuff Box.
I used this one in my center console and this one in my tuff box. Right now Im using industrial strength velcro to mount them. It doesnt look like the stick side of the velcro is liking the tuff box plastic so I may end up riveting it on and making it more permanent. I use pouches on them right now but for you gun toters you could put a holster there. Great thing about molle is that that they make of ton of mil-spec stuff for them in all sizes so you can always find something to fit.