That they are, and I picked them up from the little pull-out parts drawer at Home Depot.  Lowes had a handful last time I was there, as well.  It took me two trips a month apart to get all that I needed, and I cleaned them out both times. 
 
I also opted for the "2 in front, 1 in back" threaded rod combo, againstrecommendations.  Aside from having the power cord constantly hung up on that back rod when I am changing connections, I feel it was the right decision.