I have a HK MP5K sear gun converted from a SP89 by RDTS. Currently it has the polymer navy housing (Non ambi, older style marked "S" "E" & "F"), I want to put the ambi polymer navy housing w/ pictograms on there and was wondering about the trigger pack/guts/internals. Do I need to buy a new trigger pack or will my preexisting trigger pack fit inside the pictogram housing? My understanding is that it will fit but I would need to get the longer axle selector and ambi switches. And that if I wanted to get a burst housing I would need a burst pack, is this correct? Thanks!