Yes, she was the postmaster or postmistress at Giltedge from 20 Oct 1931 to 31 Jul 1946.
Welcome to History Hub,
In the 1930 Census her husband Edward J Barry was the postmaster
In the 1940 Census she is a widow and the Postmistress
Dear Ms. Darcy,
Thank you for posting your request on History Hub!
The source of the data in the Ancestry data collection U.S., Appointments of U. S. Postmasters, 1832-1971 shared with you by Ms. Brooks is the National Archives record series titled Records of Appointment of Postmasters and the Establishment of Post Offices, 7/1/1931 - 10/31/1971 in the Records of the Post Office Department (Record Group 28). The series includes the files Postmaster Appointments for Fergus County, Montana (Image 4) and Postmaster Appointments for Lake County, Montana (Image 10) that list the information for Postmistress Annie Barry. Please note that the title of “Lake County” appears to be a catalog error and that the file in fact lists post offices in Fergus County. We have notified the appropriate office to review and, if necessary, correct the listing.
The census records shared with you by Ms. Lane are from the Population Schedules for the 1930 Census and the Population Schedules for the 1940 Census in the Records of the Bureau of the Census (Record Group 29). The 1940 listing for Postmistress Anne Barry may be viewed online through the catalog at file 1940 Census Population Schedules - Montana - Fergus County - ED 14-24, Sheet 1B (Image 2), Line Number 42 (second from top).
The majority of the 1930 Census schedules are not yet available using the National Archives Catalog. For a list of places to view the 1930 census records online, see Search Census Records Online and Other Resources. Of the options listed, the FamilySearch page also linked by Ms. Lane is accessible with a free account.
We hope this is helpful. Best of luck with your research!