trx63 -
Looks like a pretty clean bow.
When compared to your VS135, the 1955 Cub had a fatter riser, with leather shelf under the leather grip rather than a shelf cut into the wood of the riser.
The three 1955 Clubs, that I have all have different colored glass combinations...
Brown/Gray
Red/Gray
Black/Gray
The 1956, 1957, & 1958 Cubs all had a double shelf cut into the riser like your VS135
Those three years, I have arranged in order by serial number and dated as follows...
1956 Black/Black TB802
1957 Black/Black VG219
1958 Black/Black VN 615
1958 Black/Gray VS501
I would not be surprised to learn that other glass color combinations are in existence for these three years.
Given the above, your VS315 would be dated as a 1958.
I really haven't done any extensive research on the 1956-1958 Cubs, their serial numbers or their glass colors, so do not know if my tentative guesstimation is actually correct.
Hopefully, someone who knows a lot more about this subject than I do, will chime in.