sticker/paper on panel & junction box

Just installed a 20A 2 pole breaker but it did not click when pushing onto the bus bar. It is flush with all the other breakers and it works when the power is on so is this normal? Are some breakers just push on only? It is a Siemens breaker.

Hi, I am trying to get quotes for blown-in foam insulation and I need a Electrician to certify i have no live knob and tube wiring in the house. House is prior to 1900, 4 unit. I live on the first floor and I also have finished basement. I bought the house like that. It appears that basement has all new wiring and so do various parts of the house. Common areas like the spiral staircase might have the oldest wiring, which is that stuff wrapped in asbestos i presume. Where accessible in the basement and attic I saw remnants of knob and tube wiring, but nothing live. I also went along in my apartment and took out wall plugs to see whats in there for wiring. All breaker panels have romax coming out, there are no fuse panels. Everything is Square D boxes with breakers. There are few junction boxes within few feet of the panels with romax coming in and wires that appear to be asbestos wrapped coming out. Some wire pairs are wrapped in metal ribbed tubing. So I certainly have wiring that spans decades if not centuries. Is any of the wiring shown in pics below hazard when blowing in foam or a sure sign I have live knob and tube wiring? On a side note besides opening every wall plug and switch and looking around breaker panels, is there any other way to know for sure other than gutting the walls? Thanks Petar