Untrue. Some default weapons units use have been scaled for cost, such as shock PPSH being far better than any other PPSH in the game, or assgren MP40s being stronger than Pioneer MP40s, etc. Droppable weapons will not magically change performance when picked up by another squad, an irregular LMG42 is horrible even in the hands of a grenadier, and a grenadier LMG42 is awesome even in the hands of an irregular.
True yet kinda inaccurate, effectively every single squad in the game except rear echelons has this modifier. 95% of units have 15%, a few more expensive units like shocks and PGrens and for some reason assgrens have 20%.
I wish irregulars could pick up weapons; not being able to is yet another reason they suck. I don't think the DP irregulars can even pick up their own DP if they drop it (which happens a lot). It's pretty sad.
Anyway, back on topic, if I tech zooks, I always put em on REs first as theyre great bazooka platforms.