I'm sure you'll gat many different opinions and suggestions on this, Nsclcctl..
Personnaly, I glue my tracks before painting, as I always end up painting the tracks in a dirty red-brownish black first, before doing any extra weathering... The reason I do this, is to avoid problems with glue showing up after the paint has been applied (as you know, glue will not do well on paint!), and avoid getting the paint flaking away as I twist and pull to get the tracks on (vinyl tracks of course, not the indi link ones!)
As to the gun, I like everything glued for good o my models, but I gather the majority here prefers to be able to modify the 'pose' at will.