I contacted the DC Society SAR and I have not submitted an SAR application under Peter DeSpain. Here is what they said:
"It does not appear that you, or any Compatriot for that matter, has ever filed papers claiming descent from Peter Despain/De Spain/Des Pain. However there are a few DAR applications on a Peter De Spain (c 1762 NC-3/31/1850 Green Co., KY). The SAR database also mentions Montgomery County, VA, and Rev. War Pension No. S. 14559. Footnote.com has the complete file, most of the pages of which add nothing to the record, but there are six that you may find interesting.
All the DAR apps go through one of two sons by Peter De Spain's second wife, Nancy Skaggs: Harrison (wife Isabella Towne) or Silas (wife Abigale Edwards). If that's your Peter, and you go through one of those sons. The Pension file mentions only Peter's youngest son, William Perry De Spain, born 8/2/1837.