I am the original poster and a Lamm descendant. John is my 6th great grandfather. There is an annual Lamm reunion at Hain's Church every August. There are many Lamms found in the church records for St John's/Hain's Church and they can be found at the Berks Co Historical Society.
I'm also a member of DAR. The information you can order from DAR would be an application of a past member. It does not include any proof documents and would not help unless you are researching the same line as that member used to join.
DAR does not keep information on 1812 veterans. There is a searchable index on dar.org of those Rev War patriots who have been proven, but it is not a comprehensive list of all Rev War participants.
John's father, Peter, was also a participant in the RW.