The town of Hickory was a preexisting set at the "Disney" Burbank studios. The town square or traffic circle was bordered by sidewalks, but in the shots portraying the 1930s the sidewalks were covered with dirt or sand, perhaps because playing baseball in such a small area with sidewalks seemed unrealistic (see 0:03:46 and following).
Hetty Cutler Seibert:
No one is ever alone who has something good to remember.
When Lem is selling Hetty notions in the store, he shows her patterns for dresses. The patterns are styles from the 1950's/1960's. The time period for the movie is the early 1930's.
The 1976 theatrical reissue was shortened by 10 minutes, as was the original home video. The DVD is of the complete, original version.