Thank you everyone.
Renee, Mike is Penny's CLONE! (well, plus about 15 lbs at this point) Thank heavens he finally got big enough that usually I can tell them apart, but just the other day one of them was up in the back yard barking at something, and one was at the back door, and I had to look back and forth several times before I figured out who is who.
There are also other similarities besides the way they look. Mike will step right out into your arms off the grooming table, or a stacked crate, same as Penny. Complete trust. I am amazed sometimes at how strong the inherited aspects of personality/temperament are!