yes the chain size and placement is the same.
the only real difference between the 48 cc, and the 66 cc is the bore and piston size. (besides the 48 c.c.'s with the different carb and no intake tube)
exernally they are almost identical. the cylinder on the 48 c.c. may be slightly smaller externally, but if the 48 c.c. cylinder is smaller, it's not by very much.