Yes, I ordered them together. However, if you order the Yellowstone compound separately, you get three canisters for $6.95, so I think ordering separate may save money in the long run.
1 Strop, 1 canister (package deal) $17.95
1 Strop, 3 canisters (separate) $20.90
EDIT: The picture shows three canisters, but I can't be sure you get more than one if you buy separately. The picture of the Dunkle strops shows several strops, but I'm sure you get just one.