The big McCulloch saws have a 3/8" bar stud, many bars will interchange with big old Homelites but there are quite a few McCulloch bars out there. Virtually any large saw from the D-44 forward will share bars. Some of the older direct drive saws used a screw with an oversized head to engage the bar for adjustment, but even those had the proper oiler holes and holes for the more convetional bar adjust dog.
The 10 Series McCulloch saw have 5/16" studs though you can find simple adapters that will let you use a large mount bar on the smaller saws. One style adapter is like a small spring that fits over the stud making up the difference, the other is a small sheet metal figure 8 that lays over the bar studs to take up the clearance.
I would go ahead and get a bar dedicated to the 10 Series saw as they will be narrower and therefore lighter in weight, and look better on those saws. The same bar mount (D176) will fit all 10 Series direct drive saws, the 600 Series (610, 605, etc.) and the Titan models (Titan 50/57/70, etc.).
Mark