You do get "generic" posts with your Mastercam insall disks
Mastercam will install a couple but you have to select "Instal Post Processors" to get them all
These milling posts are found in the "C:\McamX\Mill\Posts\" directory and have the extension .PST---the "C:\Mcamx\" is the install root directory
You should try all that you think would work, select the closest match, and then modify that post to suit your preferences. ( zip the rest to leave your selected files, remane it so a re-install doesn't overwrite a good modified post ).
Always copy the original post ( known working version ) before doing any mods. and only alter a small section, save, and test----extremely hard to find where you missed a comma, a dollar sign ($) etc. ---any mistakes here makes all NC code into crash fodder. The original is there to enable roll-back to lastest changes.
Editing can be done in any text editor, CimcoEdit and the Mastercam editors supplied can be used for this purpose.
a BobCAD post for a mill has the .MILLPST extension and is not compatable with Mastecam