Suzanne,
It looks like your Alexander Montgomery may be the brother to our John Montgomery. (I have not checked my information to confirm this)
If it is so then you would learn a lot about your Alexander who left a lot of descendants in Magoffin County, Kentucky. The Magoffin County Historical Society has published a family history on this Montgomery family. If they do not have one already printed , they will print one out for you. A google search will find it.
I quite agree about old and questionable records at the DAR being removed. The DAR is very conscientious nowadays. For Alexander’s brother, John I used DAR file A079041. The Sons of the American Revolution number for descendant Anderson is 182692, in state number 3750. This membership was issued in 2012. Hope this info helps.
Good luck!
Kay