Mary Hoag pulls a Winchester 1894 rifle from behind the bar, which won't be made for another 21 years at least. However, it is similar to other Winchester lever action rifles of the era in general looks. All of the handguns appear to be Colt Single Action Army revolvers which began in 1873. While it is possible for some to be there, it is doubtful that everyone would have one as they are new and guns were expensive for people then.
Set in 1873, Tom Sabin couldn't head to Tombstone as it didn't exist until 1877.