Observation of acoustics generated by a surface restricted transient optical grating can be used as a sensitive probe of interface structure that can influence near-surface chemical interactions. In this paper, a theoretical analysis is presented detailing the interface acoustic waves generated by this optical grating technique for a structure consisting of a liquid/solid interface with an interposed thin solid layer. Tn the absence of the layer, the predicted response consists of contributions from both the Stonely and the Leaky-Rayleigh wave interface modes, consistent with experimental observations. Thin intermediate layers, those with thickness much smaller than the grating period, were found to have little influence on the acoustic response indicating that the spatial sensitivity of this technique is not sufficient for probing the short range order in liquids in contact with surfaces. However, the addition of a layer with thickness on the order of the grating spacing affects the dominate period of the response as expected from the dispersion relation for the liquid/solid/solid structure. For these thick layers, bulk waves propagating across the layer thickness also initially contribute to the response.