Darren,
You´ve got yourself a nice project there!
As for serial numbers, check my
Sherman Register: Serial numbers page. You should be able to find the serial number stamped on both the front and rear towing lugs, but you can trust only the rear numbers, as the final drives were subject to replacement as the one on your tank.
There are no such things as "Sherman tracks" or "Grant tracks". Yes, M3 series medium tanks were fitted with rubber block or WE-210 at the factory, but these were swapped for any of the myriad
track types available when worn out. In this day and age, you should be happy to have a set of tracks at all.
Note: consider joining
G104 - the Sherman Register mailing list.
Is your Grant equipped with the radial engine or diesel engines?
Regards,
Hanno