I've got a Bulgarian 74 Side folder and the stock locks up seriously tight. Its good, but to release it I need to bang the plunger with something or pin the rifle in my knees and yank on the stock (towards the closed position) to allow the plunger to release. Is there a certain way to file one of the latch parts down to make this more usable? I am hesitant to just break out the dremel and end up with a floppy stock.

I took a small file to the lock up slot and went a little at a time. Works fine now.

Don't file anything. It will loosen as you use it.

It can be challenging.  One must file/sand the latch and the slot.  Lots of Dykem to assess points of binding.  

First, the stock is adjusted for angle.  The pad on the front controls its open angle.  Often this is a trapezoidal shape.  It should be rectangular.  Most of the time, I can put the latch in the mill and and skim the inside surface to get it true, then bevel the leading edge slightly.  Truing the slot in the stock with a 1/8" cutter helps too, as often it is not straight.  Roll/break the leading edge.