joco- yes- I found two more on Sunday, one more on Monday evening and one more tonight. Most are in pretty poor condition and have apparently been dead for a while.
I am currently just harvesting the cleithra and submitting them (one per fish) along with fish length and location.
Here's a shot of the cleithrum I removed tonight from a 50 incher:

I also saw a huge one floating down the River today, but was unable to locate it when I went out this evening. In addition there are others on shore that are not accessible to me.
If anyone finds a dead muskie anywhere, any time, one of these bones should be removed and submitted to the MNR. The info they can get from this source is invaluable. Age and growth rates can be determined from the "rings" in a similar way as when you age a tree by counting the rings on a stump.
CCB