Answer
Yes, with certain limitations.
Current users of ArcGIS for Windows Mobile 10.0 may want to re-use their existing mobile projects after upgrading to 10.1. Follow the instructions below to convert a 10.0 project to a 10.1 project.
A 10.0 mobile project can be created by using either the GP tool or the Mobile Project Center (MPC). At version 10.1, MPC can be used to open the 10.0 project (.amp file) from under the mobile project folder, and use File > Save As to save it as a 10.1 project. This 10.1 project can then be deployed to mobile devices and used by 10.1 field applications.
The limitation, however, is that 10.0 mobile projects don't have either Field Crew Task or Logging capability enabled. If either of them are enabled, the mobile project must be re-created with 10.1 MPC.