Most likely! Sam and Dean spend a lot of time around Bobby’s. Though it’ll be a few years before Rumsfeld is around, eventually the pup will discover the hidden burrow out in the field and chances are he’s going to want to introduce wee Sammy to his friends. Keeping Dean out of the way will be the hard part.
Arthur will not like this at all, especially since it usually ends with Dean tracking down his baby brother (Rumsfeld, you really gotta warn Dean about these things before just darting off with Sam).