+1 My favorite option is to convert to aerolevers. You can buy no name aerolevers for $11 at Niagara Cycle. That price is close to what lever hoods alone would cost.
I have also installed the Cane Creek lever hoods (about $7 at Niagara last time I bought some) and just left that small tab exposed. It looked fine IMHO. Anymore, since there is only a $4 difference between the two options (and one gives you brand new levers which much more functional hoods), I just go with Aerolevers.
If you look at this pic, you will see the red tabs on the levers.
1986 Trek 400T as found with turkey levers (missing one lever hood). FWIW: bike originally came with regular levers (no turkey levers):
After installation of Aerolevers out of the parts bin, and completion of rehab: