I recently purchased an early "60's Ludwig marching snare with Keystone badge without serial number. What is odd about this drum is it'd dimensions of 10 1/2" by 15" instead of the normal 12" by 15". It doesn't appear to have been cut down, such as there are no extra holes drilled to retrofit the strainer and muffler fittings.

It's a big drum with an odd shape. Is this a limited edition with short shell depth, any help from Ludwig experts would be appreciated.