thanks for all your replies. There is rim tape on the inside of the rims, but I'm assuming that the LBS was recommending something a bit stronger just to make sure that nothing would pop through during the ride. I did end up ordering some flat restistance tubes that I'll have them put on just to have the added insurance. I normally don't panic about flats-they happen, you stop, you fix, you continue to ride..but this biathlon is one of 12 things that I promised to do when I turned 60.-- 6 more things to do and I can move on to 61! Will keep you posted as to the outcome...again, thanks for all your help.
~AG~