From VBA code, you can check the property FileFormatto determine the file format of your MDB file. It will return the value from the class Access.AcFileFormat.
I used this in an Immediate window with MDB created as an Access 2002-2003 format.
? CurrentProject.FileFormat = acFileFormatAccess2002
True
Note that this does not say anything about the version of Access that was used to create the MDB. I created it using Access 2007:
? Access.Version
12.0
, Access, MDB, MDB. MDB , , VBScript, Access Access.
, , , Access MDB, - .