Hilt markings on horseman's sword
 

This is a horseman's sword with a 1688 blade from Shotley Bridge.
I suspect, at some point much later, part of the hilt has been replaced with what looks like a munitions grade shell and knuckle guard… and possibly a grip binding (copper).
The pommel feels original.
Can anyone identify any of the markings:
either on the shell CA (I?) M and IV / 2;
and/or the details on the pommel?

Really interesting, these British bilobate hilts!
The hilt in the 2nd photo looks like one of the heart shaped '1751' hangers while the more ornate bilobate (figure 8) in the first and the pommel in third corresponds.

I know the British thing for marking, the upper the unit number and the lower is rack number. It seems these were consistent on these British brass hilt hangers of 1740s-50s mostly with those heart shape bilobate guards and always so marked on underside.
Not sure what the CA (I)M represents but these units typically had names for the commanding officer, so and so's dragoons etc.