I believe that your 16LS2 already has the teflon caps in it. That's what the 2 at the end signifies.
If your amp is suited to your speakers (I don't know if it is or not) the newer c-j preamps use only one or two tubes making them much cheaper to tube roll than the 16LS2.
If your amp is suited to your speakers (I don't know if it is or not) the newer c-j preamps use only one or two tubes making them much cheaper to tube roll than the 16LS2.