Depends. Do you want cowboys with lariats herding cattle? Then, yes, but availability might be iffy - Musket Minis had some in the Rustic Rails range for N-scale. If you mean gunmen, don't know. But Irregular does have 10 mm Plains Wars warriors.
edit: Irregular tend on the larger size for 10 mm so might fit well with Peter Pig's small 15s. But Irregular will likely be stockier sculpts.