For mod, You can create a gadget,
function gadget:UnitDestroyed(unitID, unitDefID, unitTeam, attackerID, attackerDefID, attackerTeam)
local gunshipbomb_udid=UnitDefNames.gunshipbomb.id
if unitDefId==gunshipbomb_udid then
local x,y,z=Spring.GetUnitPosition(unitID)
local teamID=Spring.GetUnitTeam(unitID)
Spring.CreateUnit(gunshipbomb_udid,x,y,z,0,)
end
end
for tweak, you can customParams.spawns_name= unit name (irrc you said that)
e.g. {gunshipbomb={weaponDefs={gunshipbomb_bomb={customParams={spawns_name="gunshipbomb"}}}}}