I’d imagine most people with the knowledge to safely handle these types of explosives already have access to modern weapons grade stuff (black market munitions,

I’d imagine most people with the knowledge to safely handle these types of explosives already have access to modern weapons grade stuff (black market munitions, etc.). For your run of the mill domestic terrorist type it really isn’t that hard to make explosives (fertilizer and diesel fuel), so probably not worth the risk of messing with unstable 100 year old bombs.