Do GNUmakefile, GNUmakefile.am, and GNUmakefile.in indicate that Automake has been used?

The source folder of rtnet contains only the above mentioned files for compilation purposes. Remaining files are the source code of the examples. Question is that do these files indicate that they have been generated through automake? If yes, then where should I look to find out what settings where made to configure automake for generating these files?