I've looked in the Registry, and database BizTalkMgmtDb.dbo.BizTalkDBVersion to try to determine of Biztalk 2010 or BizTalk 2010 R2 is installed on my system.
What's unclear is how R2 would show up there, is it part of the product name itself?
RegEdit:
SQL Query:
List of BizTalks Available to Download from MSDN:
This is the announcement of BizTalk 2010/R2 in Dec 2011: https://blogs.msdn.microsoft.com/biztalk_server_team_blog/2011/12/08/biztalk-server-2010-r2/