I think this is the pension record for your ancestor whom shows a Sarah J. Mantania.
Name: Albert Mantania Event Type: Military Service Event Date: 16 Aug 1862 Event Place: Potter, Pennsylvania, United States Event Place (Original): Potter Co Pa Age: 39 Military Regiment: Infantry Military Company: Co K 149th Term of Enlistment: 3 Yr Birth Year (Estimated): 1823 Note: Transfd To V R L Sep 16/63 G O No312 Page Number: 113
Looks like he was transferred according to GO#312 to Veterans Reserve Corps (V.R.C) date Sept 16th 1863 so if he was transferred prior to the battle of Gettysburg from the 149th then its possible he was not at the Battle of Gettysburg.
Please see also where he is buried. Copy and paste link into your web browser.
Here is his units roster please see him below near bottom of roster.
Dear Mr. Herbstritt,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located the series Indexes to the Carded Records of Soldiers Who Served in Volunteer Organizations During the Civil War, 1899 - 1927 in the Records of the Adjutant General's Office, 1762 - 1917 (Record Group 94) which include index cards for [Pennsylvania] Mantania, Albert - 149th Infantry, Company K, Mantania, Albert - Unit: 149th Infantry, Company: K - Enlistment Rank: Pvt, Discharge Rank: Pvt, and Mantania, Albert - 2nd Battalion, Veteran Reserve Corps, Company 7.
The index cards indicate there should be compiled military service records for Albert Mantania in the series Carded Records Showing Military Service of Soldiers Who Fought in Volunteer Organizations During the American Civil War in the Record Group 94. Most of the service records in this series have been made available via microfilm and through digitization of the microfilm. Unfortunately, the records for Pennsylvania Volunteers have not been microfilmed or digitized. Also, the pension index card that Mr. Schneider shared indicates that there should be a pension file for him. The files have not been digitized yet.
To order records that have not already been digitized, please fill out a NATF Form 86 for the service records and a NATF Form 85 for the pension records and mail the completed forms to the address listed on the form. You also may place your order online using eservices.archives.gov. For more information see Requesting Copies of Older (pre-WWI) Military Service Records.
Please note that the National Archives and Records Administration (NARA) has suspended reproduction and digitization services until further notice due to COVID-19. Orders will not be serviced until operations can resume safely. Once operations resume, document reproduction requests will be filled in the order in which they were received. We apologize for any inconvenience.
The Veteran Reserve Corps (originally, called the Invalid Corps) was a military reserve organization created within the Union Army during the American Civil War to allow partially disabled or otherwise infirm soldiers (or former soldiers) to perform light duty, freeing able-bodied soldiers to serve on the front lines. Albert Mantania’s transfer to this organization probably indicates that he experienced an injury or illness that prevented front line service. There may be further details about this in his pension files.
We hope this information is helpful. Best of luck with your research!