That they are. I remember having to have mine replaced on my very first PL700B. The guy I bought it from had tied the wires together and bypassed the switch. The guts of the switch all missing. I didn't find this out till years later. At the ripe ol age of 17, I just figured "meh" i guess this switch doesnt do anything really. Maybe its in a sonic range I can't hear? Ohhh how nieve.
I had to have Alpha Tech Electronics (a local vintage audio repair shop here) replace it. And aparently it is VERY hard to find a D-shaft, DPDT switch. (I "think" this is what it is. Correct me please if I'm wrong). He said he had to get it ordered in from Lithuania?! I found it hard to believe you can't find something like that in the states. Came in a pack of three and he couldn't just buy the one and had no use for the other two so he charged me for all 3. But whatever....I wanted it working that bad. Today, Jerry now has that amp.
Best bet is to buy a junker off ebay and have some spare parts. OR.......maybe the almighty Lee has one laying around? He's got almost everything!