Also worth mentioning. If you look at pictures of the prop guards, it's very obvious that there are a lot of variations of them.
Compare:
Notice that the guard rails are very flat. 2 pairs of cross braces. The lower set is almost horizontal and the top set is heavily angled down. I believe the vertical bar there is a temporary construction support, but I'm not 100% sure on that.
Here's a couple of photos from the wreckage of the grunion:
Notice that the cross braces on the topside are nearly horizontal and the bottom braces are angled sharply, the opposite of the above. Also notice that the forward side is angled more than the stern side. Again, the opposite of permit.
Silversides:
Just completely different, I believe that this is the bolt on setup as evidenced by the next photo.
Silversides without guards:
Silversides Today:
Notice the configuration changed sometime after the above picture was taken. I don't know when.
Barb:
No guards at all.
Cod today:
Again, completely different.