Hi Boxxman, you could start using the LNB as is simply by taking a pair of needle nose pliers and wrapping the tips with tape and gently move the probe inside the feedhorn to either vertical or horizontal polarity. Makes for a good test of the LNB and if it is still good you would be able to get half of the TPs.
BTW - the old LNB (provided it is still good) will work great on HD, I can even receive the DVB-S2 stuff and I have the same LNB.
Hope this helps, DC