1954 - 3100 - Transmission bolts

[Fred n' Ethel]

Is this just a coincidence ?
I now have 2, 54-1300 drive lines that have no bolt heads at the lower 2 ears of the transmission to bell housing fastening.
Is this a common occurrence in any of your experiences ?
Seems strange that they would be pins.
Should be bolted as the top 2 are .... surely. ?
I'll brush them up to see if it looks like a fracture.
Maybe many of these seized and were rung off during an attempted disassembly ? ... then were left like that ? What a mechanic, huh ?
Thanks.