oledb - EXCEL 2007 VBA ADODB "External table is not in expected format." error connecting to .XLTM template file

Question

I have about 200 large Excel template (.xltm) files which each contain several tables of data across multiple worksheets. I want to retrieve this data without having to open each file individually, which is very time consuming.

So far, I have been successful at retrieving the data from the same files but saved as macro-enabled workbooks (.xlsm) using the following code:

Set cn = CreateObject("ADODB.Connection")
With cn
 .Provider = "Microsoft.ACE.OLEDB.12.0"
  .ConnectionString = "Data Source=C:\Users\...REPORT TEMPLATE.xlsm" & _
  ";Extended Properties=""Excel 12.0;HDR=YES;IMEX=1"";"""

However, I get the runtime error message "External table is not in expected format." when I attempt to access the file as a template (.xltm extension), as shown below:

Set cn = CreateObject("ADODB.Connection")
With cn
 .Provider = "Microsoft.ACE.OLEDB.12.0"
  .ConnectionString = "Data Source=C:\Users\...REPORT TEMPLATE.xltm" & _
  ";Extended Properties=""Excel 12.0;HDR=YES;IMEX=1"";"""

My question: is there a way to use ADODB to retrieve data from a .xltm file in Excel 2007?