Restore database created in SQL Server 2008 R2 to SQL Server 2008 R2 SP2

I have a .bak file created by some other user in (I think) SQL Server 2008 R2 (10.50) and I need to restore it in SQL Server R2 SP2 (10.52). I used a hex viewer to look into the .bak file and found out a string containing something like "MSSQL10_50.SQL...", so that's how I guessed it was created in R2.

I get errors when trying to restore it from Management Studio interface, and also when I try to only verify the .bak file using T-SQL:

RESTORE VERIFYONLY FROM DISK = N'D:\aep_p.bak'
GO

I get:

Msg 3241, Level 16, State 13, Line 1
The media family on device 'D:\aep_p.bak' is incorrectly formed. SQL Server cannot process this media family.
Msg 3013, Level 16, State 1, Line 1
VERIFY DATABASE is terminating abnormally.

My questions are:

1. Is it possible to restore a .bak from R2 to R2 SP2?
2. If yes, then why do I get that error?