IRL the WAR HUD is indeed a purchase option for Block 50/52/52+ aircraft. Some of the RSAF F-16D-52+ birds have them installed as seen in these pics.
https://scontent-sjc2-1.xx.fbcdn.net/t31.0-8/12188077_786056794836180_8669460206348079562_o.jpg
https://scontent-sjc2-1.xx.fbcdn.net/t31.0-8/12185386_786056491502877_8940508323285352784_o.jpg
https://scontent-sjc2-1.xx.fbcdn.net/t31.0-8/12186445_786077104834149_7706578800467054799_o.jpg
Well a simple quick way I think would be just to change the block 52 3dckpit.dat to use block 40, I think these three lines might do it, but could be wrong?, never tried.
try changing these 3 lines in block 52 3dckpit.dat: C:\Falcon BMS 4.33 U1\Data\Art\ckptart\F-16CM-52
cockpitmodel3 3;
cockpithudmodel 4;
cockpitcanopymodel 5;
to this:
cockpitmodel3 3090;
cockpithudmodel 3091;
cockpitcanopymodel 3092;
?