It's an interesting theory and very likely to be true.
I found two points that may confirm it.
First Ruby and Summer have the same emblem : a beautiful rose (except for the color summer emblem is white and rube's one is red), the only other character who have inherit his emblem is Weiss Schnee who clearly have an hereditary semblance, plus Ruby also inherit her first name "Rose" from her mother (unlike her sister who took the father name).
I consider this point has a good argument for your theory because of the other theory who say that Weiss has an hereditary semblance because she's from a long and important dynasty (maybe even some royalty) and she consider her family legacy as a primary part of her personality. All this can also be said for ruby and her mother and it's support by the lyrics of the song "red like roses part 2" and the heredity of the silver eyes who imply a very long family history.
The second point is the scene at the beginning of the opening of Volume 1 . We saw Ruby and Summer's "ghost" use the same semblance together (except for the color) .
This is a strong enough point to make me think your theory is indeed true.
About considering the silver eyes has a second semblance or the second "level" of her semblance, it's possible especially since Weiss also have a two part semblance (glyph and summon).